{"id":5220,"date":"2026-09-18T07:49:08","date_gmt":"2026-09-18T07:49:08","guid":{"rendered":"https:\/\/www.henghuahose.com\/?post_type=product&p=5220"},"modified":"2026-09-18T07:49:14","modified_gmt":"2026-09-18T07:49:14","slug":"sae-o-ring-boss-l-series-iso-11926-3-npt-female-adapter-5on","status":"publish","type":"product","link":"https:\/\/www.henghuahose.com\/ar\/product\/sae-o-ring-boss-l-series-iso-11926-3-npt-female-adapter-5on\/","title":{"rendered":"5ON Adapter – SAE O-Ring Boss L-Series ISO 11926-3 to NPT Female Hydraulic Adapter"},"content":{"rendered":"
The 5ON adapter is a straight cross standard adapter that joins a SAE O-ring boss port to a female NPT port. Its E end is a SAE J1926-3 \/ ISO 11926-3 light-duty L series straight thread stud with an O-ring groove, and its F end is a tapped NPT taper thread. The 5ON adapter therefore carries two sealing principles in one body: an elastomer seal at the boss end and a sealed pipe thread at the female end.<\/p>\r\n\r\n\r\n\r\n
Both connection ends must match their mating port exactly in thread form, size and sealing geometry, because that exact match is the precondition for eliminating leakage at the conversion point.<\/p>\r\n\r\n\r\n\r\n
Sealing principle of this series: the E end seals with an O-ring held in a groove on the straight thread stud end and compressed against the port spot face as the lock nut is drawn down. The F end seals on the NPT thread flanks and needs a thread sealant, or an NPTF dryseal thread pair per SAE J476. This series does not seal on a 37\u00b0 flare, on a 74\u00b0 cone, on an ORFS flat face or on a four-bolt flange.<\/p>\r\n\r\n\r\n\r\n
Core Advantages<\/h2>\r\n\r\n\r\n\r\n
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SAE O-ring boss adapter design, with the stud end made to SAE J1926-3 \/ ISO 11926-3 and matched to the SAE J1926-1 \/ ISO 11926-1 port.<\/li>\r\n\r\n\r\n\r\n
Internal NPT thread tapped to ANSI\/ASME B1.20.1, with NPTF dryseal to SAE J476 as the pressure-tight option.<\/li>\r\n\r\n\r\n\r\n
27 printed part numbers, from a 5\/16″x24 boss to a 2.1\/2″x12 boss, in matched and reducing combinations.<\/li>\r\n\r\n\r\n\r\n
An O-ring code published for every row, O902 to O932, so the boss seal is ordered with the adapter.<\/li>\r\n\r\n\r\n\r\n
Carbon steel with trivalent chromium zinc plating, or 304 \/ 316 stainless steel for corrosive service.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
1. What a 5ON Adapter Does<\/h2>\r\n\r\n\r\n\r\n
A 5ON adapter converts one port standard to another on a single axis. The stud end screws into a straight thread O-ring boss port, and the tapped end accepts a male NPT pipe thread. Flow direction does not change: what enters the E end leaves the F end on the same centre line.<\/p>\r\n\r\n\r\n\r\n
The 5ON adapter exists because the two ports on a machine are not always built to the same convention. A pump, valve or manifold may be machined with an O-ring boss port to SAE J1926-1 \/ ISO 11926-1, while the line that reaches it is terminated with an NPT pipe thread. Doing that conversion with two stacked parts adds a second threaded joint and a second leak path; this thread adapter does it in one body.<\/p>\r\n\r\n\r\n\r\n
The stud end is a straight thread, not a taper. It carries an O-ring in a groove behind the thread and is locked by a nut against the spot face of the port. That is the defining feature of the O-ring boss family: the threads hold the joint together, the O-ring performs the sealing, and compression is set by a controlled face contact rather than by thread interference.<\/p>\r\n\r\n\r\n\r\n
2. 5ON Specifications<\/h2>\r\n\r\n\r\n\r\n
The two ends are presented as mirrored blocks. Read the E block for the boss port and the F block for the pipe port, then confirm both against the mating hardware.<\/p>\r\n\r\n\r\n\r\n
2.1 Connection 1 – SAE O-ring boss male stud end (E)<\/h3>\r\n\r\n\r\n\r\n
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Thread standard and family: straight thread O-ring boss stud end to SAE J1926-3 \/ ISO 11926-3, light-duty L series. The matching port is a SAE J1926-1 \/ ISO 11926-1 straight thread O-ring boss port.<\/li>\r\n\r\n\r\n\r\n
Thread size range available at E: 5\/16″x24 (size code 02) through 2.1\/2″x12 (size code 32), in the steps printed in table 2.5.<\/li>\r\n\r\n\r\n\r\n
Gender: male stud end with a straight, parallel thread.<\/li>\r\n\r\n\r\n\r\n
Sealing method: elastomer O-ring seated in a machined groove on the stud end and compressed against the port spot face; the lock nut supplies the clamping load and sets the compression. The threads do not seal.<\/li>\r\n\r\n\r\n\r\n
Mating port standard: SAE J1926-1 \/ ISO 11926-1 O-ring boss port with a machined spot face and the corresponding boss diameter.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Thread standard and family: American tapered pipe thread NPT to ANSI\/ASME B1.20.1, with NPTF dryseal threads to SAE J476 as the pressure-tight option.<\/li>\r\n\r\n\r\n\r\n
Thread size range available at F: Z1\/8″X27 through Z2″X11.5, read from the F column of table 2.5.<\/li>\r\n\r\n\r\n\r\n
Gender: female, an internal thread tapped into the body of the adapter.<\/li>\r\n\r\n\r\n\r\n
Sealing method: metal-to-metal contact on the thread flanks, with a thread sealant applied by the installer, or an NPTF dryseal pair that is pressure tight on the threads themselves.<\/li>\r\n\r\n\r\n\r\n
Mating port standard: a male NPT or NPTF pipe thread, or an NPT hose tail and coupling of the same nominal size and pitch.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
The two ends are not the same family and not the same sealing type. The E end is a straight thread with an O-ring; the F end is a taper thread with no elastomer in the sealing path. Read the E and F columns as two different interfaces, not as two sizes of one interface.<\/p>\r\n\r\n\r\n\r\n
2.3 Construction and Materials<\/h3>\r\n\r\n\r\n\r\n
The body is machined from bar stock on CNC lathes. The boss end is turned as a straight thread with its O-ring groove and boss diameter, the female end is drilled and tapped with the NPT taper, and the hex is formed in the same setup.<\/p>\r\n\r\n\r\n\r\n
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Body material: carbon steel as standard; 304 stainless steel, 316 stainless steel or brass on request.<\/li>\r\n\r\n\r\n\r\n
Plating: trivalent chromium zinc plating (Cr3+) for carbon steel as standard; zinc-nickel plating available. Plating thickness and corrosion performance are confirmed per order rather than published as a series figure.<\/li>\r\n\r\n\r\n\r\n
Seal material options for the O-ring: NBR, FKM (Viton-type) and EPDM, selected to match the fluid and the temperature of the circuit.<\/li>\r\n\r\n\r\n\r\n
Machining process: bar-stock turning, straight thread form produced to the port standard, O-ring groove checked against the drawing, NPT thread tapped and gauged.<\/li>\r\n\r\n\r\n\r\n
Hex feature: a single hex (S1) on the body, from 17 mm to 70 mm across flats depending on size. There is no bulkhead feature in this series.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
2.4 Pressure and Temperature<\/h3>\r\n\r\n\r\n\r\n
Working pressure for a 5ON adapter is not set by the series code. It is governed by the thread size, the wall thickness of the body, the sealing method at each end and the material selected, and it is further limited by the two ports it joins. Working pressure for these sizes is confirmed per order by HENGHUA engineering, based on the thread size, sealing method and material selected.<\/p>\r\n\r\n\r\n\r\n
Temperature is a material fact here. For NBR seals the working range is approximately -30\u00b0C to +100\u00b0C; for FKM (Viton-type) seals approximately -20\u00b0C to +200\u00b0C; for EPDM seals approximately -40\u00b0C to +120\u00b0C. On this series the elastomer is the O-ring at the boss end. Carbon steel with zinc plating suits general service; specify 304 or 316 stainless steel for corrosive environments.<\/p>\r\n\r\n\r\n\r\n
2.5 Part Number and Dimension Table<\/h3>\r\n\r\n\r\n\r\n
The table below is the complete printed size range of the series. All length and hex dimensions are in millimetres. The O-ring column records the seal for the E end.<\/p>\r\n\r\n\r\n\r\n
What each column means<\/strong><\/p>\r\n\r\n\r\n\r\n
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PART NO.<\/strong> – the HENGHUA part number. The prefix 5ON<\/code> is followed by one size code for a matched part, or by two size codes separated by a dash when the boss size and the pipe size differ.<\/li>\r\n\r\n\r\n\r\n
E<\/strong> – the thread of connection 1 of this SAE O-ring boss adapter, printed as diameter x threads per inch, for example 7\/16\"X20<\/code>.<\/li>\r\n\r\n\r\n\r\n
F<\/strong> – the thread of connection 2, the NPT female taper thread. Z<\/code> marks the American tapered pipe thread, the fraction is the nominal pipe size and the number after X<\/code> is the pitch in threads per inch, so Z3\/8\"X18<\/code> is a 3\/8″ NPT thread at 18 threads per inch.<\/li>\r\n\r\n\r\n\r\n
O-RING E END<\/strong> – the O-ring code published for the E end of that row, from O902 at the smallest boss to O932 at the largest.<\/li>\r\n\r\n\r\n\r\n
A<\/strong> – the boss length at the E end, in millimetres, as marked on the series drawing.<\/li>\r\n\r\n\r\n\r\n
L<\/strong> – the overall length in millimetres, from the end face of the boss stud to the outer face of the female end.<\/li>\r\n\r\n\r\n\r\n
S1<\/strong> – the hex across flats in millimetres, the wrench size used to hold the body during assembly.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Thread size and dash chart<\/strong><\/p>\r\n\r\n\r\n\r\n
The dash code is the size step, and in this series it follows the SAE O-ring boss stud end.<\/p>\r\n\r\n\r\n\r\n
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Size code<\/th>\r\n
Boss thread at E<\/th>\r\n
NPT size at F on the matched row<\/th>\r\n<\/tr>\r\n<\/thead>\r\n
Codes 03 and 05 appear in the printed table only in reducing rows, so no single NPT size is attached to them above. The F column of table 2.5 governs in every case.<\/p>\r\n\r\n\r\n\r\n
3. How to Read a 5ON Part Number<\/h2>\r\n\r\n\r\n\r\n
A 5ON part number has three elements: the series prefix, the boss size code and the pipe size code.<\/p>\r\n\r\n\r\n\r\n
The prefix 5ON<\/code> identifies the family: a straight cross standard adapter with a SAE O-ring boss L-series stud end to SAE J1926-3 \/ ISO 11926-3 and a female NPT end. A different prefix in the same catalogue identifies a different geometry or a different pair of interfaces, such as a JIC 74\u00b0 cone end, an elbow body or another thread adapter.<\/p>\r\n\r\n\r\n\r\n
The first size code is the E end, the O-ring boss stud, and it follows the SAE dash convention: 04 is the 7\/16″x20 boss, 06 is the 9\/16″x18 boss and 08 is the 3\/4″x16 boss. A second size code, when present, is the F end, the NPT female thread, expressed as a pipe dash number. The second code is not always the larger of the two: rows such as 5ON-10-06 place a larger boss at E and a smaller pipe thread at F, so read both columns.<\/p>\r\n\r\n\r\n\r\n
Worked example: 5ON-10-06.<\/strong><\/p>\r\n\r\n\r\n\r\n
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5ON<\/code> – straight SAE O-ring boss to NPT female adapter.<\/li>\r\n\r\n\r\n\r\n
10<\/code> – connection 1 is the 7\/8″x14 SAE O-ring boss stud end, with O-ring O910.<\/li>\r\n\r\n\r\n\r\n
06<\/code> – connection 2 is the Z3\/8″X18 NPT female thread.<\/li>\r\n\r\n\r\n\r\n
From the table: A is 12.7 mm, L is 35.5 mm and S1 is 27 mm.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
No suffix is applied to any row of this table; if a suffix appears on your drawing, quote the full part number including it.<\/p>\r\n\r\n\r\n\r\n
4. Installation and Fitment<\/h2>\r\n\r\n\r\n\r\n
The two ends are made up in different ways, and the order of assembly matters. HENGHUA does not publish a single torque figure for the 5ON adapter, because the correct tightening depends on the port material, the boss size and the seal selected. Follow the port maker’s recommendation, or confirm the figure with HENGHUA per order.<\/p>\r\n\r\n\r\n\r\n
Boss end.<\/strong> Lubricate the O-ring with a fluid compatible with the system, seat it in the groove without twisting it, and insert the stud into the port. Run the lock nut down by hand, then bring it up against the spot face with the correct wrench on the hex S1. The nut supplies the clamping load and the O-ring supplies the seal, so do not use thread tape on a boss stud.<\/p>\r\n\r\n\r\n\r\n
Pipe end.<\/strong> Clean both threads, then apply a sealant compatible with the fluid and the system temperature, leaving the first thread at the entry clean so no tape fragment can enter the circuit. Bring the male part in finger-tight, then snug it and continue only as far as the port maker’s specification requires.<\/p>\r\n\r\n\r\n\r\n
Contamination and reuse.<\/strong> Cap both ends before storage, because debris that reaches the O-ring groove or the pipe thread scores the sealing surfaces. The body can be reused if the boss face, the groove and both threads are undamaged, but the O-ring is a wear item and is replaced every time the joint is broken.<\/p>\r\n\r\n\r\n\r\n
Common fitment errors and their symptoms:<\/p>\r\n\r\n\r\n\r\n
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Fitting an NPT end to a BSPT port. Symptom: the threads bind after two or three turns and then weep.<\/li>\r\n\r\n\r\n\r\n
Reusing an old O-ring. Symptom: a slow seep at the boss end when the system reaches temperature.<\/li>\r\n\r\n\r\n\r\n
Over-tightening the pipe end to stop a weep. Symptom: a cracked port boss or a split female thread.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Confirm the part number against the line list and check that the E end matches the boss port and the F end matches the pipe thread.<\/li>\r\n\r\n\r\n\r\n
Inspect the boss face, the O-ring groove, both threads and the mating port for nicks and previous overtightening marks.<\/li>\r\n\r\n\r\n\r\n
Fit a new O-ring of the listed code in the compound selected for the fluid.<\/li>\r\n\r\n\r\n\r\n
Insert the boss stud, run the lock nut down by hand, then tighten the nut against the spot face.<\/li>\r\n\r\n\r\n\r\n
Apply the selected thread sealant to the male pipe thread and make up the female end finger-tight, then snug it without forcing.<\/li>\r\n\r\n\r\n\r\n
Pressurise the circuit, check both joints for weeping, and re-check after the first thermal cycle.<\/li>\r\n<\/ol>\r\n\r\n\r\n\r\n
5. Applications and Industries<\/h2>\r\n\r\n\r\n\r\n
Application tags for this series: hydraulic systems, water jetting, oil and gas, industrial equipment, construction machinery, agriculture, marine, material handling. A hydraulic adapter of this type is specified by its port standards rather than by industry, so one part serves several sectors.<\/p>\r\n\r\n\r\n\r\n
Cross-standard equipment integration.<\/strong> A machine assembled from components built to different conventions is the classic home of this series. A pump or manifold with a SAE J1926-1 \/ ISO 11926-1 boss port connects directly to an NPT-terminated line without an intermediate bushing, and a row such as 5ON-08-04 brings a 3\/4″ boss down to a 1\/4″ pipe thread in one part.<\/p>\r\n\r\n\r\n\r\n
Repair and replacement.<\/strong> Maintenance crews use this adapter when a damaged pipe end or a seized boss stud has to be replaced on site. Because the table covers the boss and the pipe side in one printed range, the replacement is normally drawn from stock.<\/p>\r\n\r\n\r\n\r\n
High-pressure test benches.<\/strong> Test rigs need repeatable, replaceable interfaces between the pump side, the gauge line and the test article. The O-ring boss end gives a face seal that is broken and remade without disturbing the port thread, and the single hex holds the body while the pipe end is made up.<\/p>\r\n\r\n\r\n\r\n
6. Replacement and Cross-Reference Guide<\/h2>\r\n\r\n\r\n\r\n
Cross-reference for this series is organised by standard and sealing method, never by brand. Two thread adapter types interchange only if the standard, the thread size, the sealing method and the seat or face geometry all match.<\/p>\r\n\r\n\r\n\r\n
A 5ON adapter is a cross standard adapter on two different families: a SAE J1926-3 \/ ISO 11926-3 straight thread O-ring boss stud end with an O-ring seal and a lock nut, and an ANSI\/ASME B1.20.1 NPT female taper thread that seals on the thread flanks. It is not interchangeable with a JIC 37\u00b0 flare fitting, which seals metal-to-metal on a conical flare face under SAE J514, nor with an ORFS fitting, which seals a flat face against an elastomeric O-ring under SAE J1453. It is not a BSPT part either, because BSPT is a 55\u00b0 taper thread under ISO 7-1 and will not seal against a 60\u00b0 NPT thread.<\/p>\r\n\r\n\r\n\r\n
To identify the correct replacement, measure three things.<\/p>\r\n\r\n\r\n\r\n
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Thread.<\/strong> On the boss side, measure the outside diameter and pitch of the straight thread: a 7\/16″ boss measures about 11.1 mm outside diameter with 20 threads per inch. On the pipe side, measure the outside diameter at the thread: a 3\/8″ NPT measures about 16.7 mm with 18 threads per inch.<\/li>\r\n\r\n\r\n\r\n
Boss geometry and seal.<\/strong> Confirm that the port has a spot face and that the stud end carries an O-ring groove. A SAE O-ring boss adapter always has a groove; a part with no groove and no O-ring belongs to a different family, however similar the thread looks.<\/li>\r\n\r\n\r\n\r\n
Seat type at the pipe end.<\/strong> Confirm whether the pipe joint relies on the thread flanks alone or on an elastomeric seat. A female adapter with an NPT end has no elastomer in the sealing path; a port with a 60\u00b0 cone or a bonded washer belongs to the ISO 228-1 \/ ISO 1179 or JIS family and needs a different part.<\/li>\r\n<\/ol>\r\n\r\n\r\n\r\n
Where the port standard is neither SAE J1926-3 nor NPT, a different cross standard adapter of the same size is the correct part rather than a forced thread. Record the three measurements with the part number so HENGHUA can match the replacement to a printed size code.<\/p>\r\n\r\n\r\n\r\n
7. Ordering, Packaging and Delivery<\/h2>\r\n\r\n\r\n\r\n
To order, give the following information:<\/p>\r\n\r\n\r\n\r\n
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Series code: 5ON<\/code>.<\/li>\r\n\r\n\r\n\r\n
Full part number, for example 5ON-10-06, taken from table 2.5.<\/li>\r\n\r\n\r\n\r\n
The two thread sizes, read from the E and F columns.<\/li>\r\n\r\n\r\n\r\n
O-ring code and compound: O902 to O932 as printed for the row, in NBR, FKM or EPDM.<\/li>\r\n\r\n\r\n\r\n
Body material and plating: carbon steel with trivalent chromium zinc plating, zinc-nickel plating, or 304 or 316 stainless steel.<\/li>\r\n\r\n\r\n\r\n
Quantity, destination and the packing format required.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Packaging formats: bulk cartons for line-side consumption, small boxes for distributor shelves and labelled bags for service kits, each labelled with the part number, thread sizes, O-ring code and quantity. Sample orders and first-article parts are available for OEM programmes, including drawing-based manufacture of specials.<\/p>\r\n\r\n\r\n\r\n
Lead time is confirmed per order and depends on size, material, plating and quantity. As a hydraulic adapter manufacturer and hydraulic adapter supplier, HENGHUA can quote the SAE O-ring boss adapter, the lock nut and the O-ring as one matched kit.<\/p>\r\n\r\n\r\n\r\n
8. FAQ<\/h2>\r\n\r\n\r\n\r\n
What is the difference between JIC 37\u00b0 flare and ORFS, and which should I use?<\/strong><\/p>\r\n\r\n\r\n\r\n
A JIC 37\u00b0 flare joint seals metal-to-metal on a 37\u00b0 conical flare face under SAE J514. An ORFS joint seals a flat face against an elastomeric O-ring under SAE J1453. Choose the family that matches the port already on the equipment, because the two are not interchangeable. This series is in neither family: it uses a straight thread O-ring boss at one end and an NPT taper thread at the other.<\/p>\r\n\r\n\r\n\r\n
Can NPT and BSPT be interchanged?<\/strong><\/p>\r\n\r\n\r\n\r\n
No. NPT is a 60\u00b0 taper pipe thread under ANSI\/ASME B1.20.1, and BSPT is a 55\u00b0 taper pipe thread under ISO 7-1. The form, angle and pitch differ, so the two will not seal even when a few threads start by hand. Use the thread the port is machined to, and order a cross standard adapter when the two sides differ.<\/p>\r\n\r\n\r\n\r\n
How do I identify the correct 5ON size?<\/strong><\/p>\r\n\r\n\r\n\r\n
Measure the straight thread of the O-ring boss port and the taper thread of the pipe port, then read across the E and F columns of table 2.5. When the boss thread, the pipe thread and the O-ring code all match a printed row, that row is the correct part number. Confirm the boss spot face too, because a thread that looks right can belong to a different boss series.<\/p>\r\n\r\n\r\n\r\n
What seal material should I select for my fluid and temperature?<\/strong><\/p>\r\n\r\n\r\n\r\n
For general mineral hydraulic oil within -30\u00b0C to +100\u00b0C, NBR is the usual choice. For higher temperatures up to approximately +200\u00b0C, or where the fluid attacks NBR, choose FKM (Viton-type). For water, water-glycol and many water-based fluids, EPDM is the option, with a working range of approximately -40\u00b0C to +120\u00b0C. On this series the seal material applies to the O-ring at the boss end and to the sealant chosen for the pipe end.<\/p>\r\n\r\n\r\n\r\n
How is the working pressure of this adapter determined?<\/strong><\/p>\r\n\r\n\r\n\r\n
Working pressure is not fixed by the series code. It is governed by the thread size, the wall thickness of the body, the sealing method at each end and the material selected, and it is limited by the two ports it joins. Working pressure for these sizes is confirmed per order by HENGHUA engineering, based on the thread size, sealing method and material selected.<\/p>\r\n\r\n\r\n\r\n
What is the minimum order quantity and can I get samples?<\/strong><\/p>\r\n\r\n\r\n\r\n
Minimum order quantity depends on the size code, the material, the plating and the O-ring compound, so it is confirmed with the quotation rather than published as one series figure. Samples and validation parts are available for OEM and distributor evaluation.<\/p>\r\n\r\n\r\n\r\n
Is the O-ring supplied with the 5ON adapter?<\/strong><\/p>\r\n\r\n\r\n\r\n
The O-ring is listed for every row of table 2.5 as a separate code, from O902 to O932, so it is ordered as a line item and its compound is chosen for the fluid. Quote both the adapter part number and the O-ring code on the order, and they can be packed together as a matched kit.<\/p>\r\n\r\n\r\n\r\n
Send your requirement to HENGHUA<\/strong><\/p>\r\n\r\n\r\n\r\n
Send the part number, the boss thread, the NPT thread, the O-ring code and compound, the material and plating, and the quantity. HENGHUA confirms the match to the printed table, the seal options and the delivery schedule, and quotes the 5ON adapter that fits your circuit.<\/p>\r\n\r\n\r\n\r\n
![\"5ON](\"https:\/\/www.henghuahose.com\/wp-content\/uploads\/2026\/09\/sae-o-ring-boss-l-series-iso-11926-3-npt-female-adapter-5on-dimensions.png\")
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