体裁：对比文（横向对比意图）

Intro — Same Standard, Different Profiles

If you have worked with hydraulic quick couplings for more than a week, you have met the ISO 7241 confusion. Two coupling profiles share the same standard number, they are both called “ISO 7241”, they are both ball-lock quick disconnects — and they do not fit each other.

ISO 7241-1 defines two interchangeable profiles for hydraulic quick-action couplings:

• Series A — the global general-purpose profile, adopted as the national standard in many countries (including the US, Germany and Japan)
• Series B — the European-style general-purpose profile, widespread in agriculture, construction and machinery made in Europe

A Series A male half will not latch into a Series B female half, and vice versa. They look similar at a glance, which is exactly why buyers order the wrong one — and why “ISO 7241” alone is not enough information for a supplier.

This guide explains the practical differences, how to tell them apart from the part number or the physical part, and what to specify so you never order the wrong family again.

The Two Profiles in One Table

Attribute	ISO 7241-1 Series A	ISO 7241-1 Series B
Common names	ISO-A, ISO 7241-A, “Parker 6600 profile”	ISO-B, ISO 7241-B, “Stucchi IRB profile”, “DNP HNV profile”
Locking	Ball-lock sleeve	Ball-lock sleeve
Valve type	Poppet (spring-loaded)	Poppet (spring-loaded)
Typical sizes	1/4”, 3/8”, 1/2”, 3/4”, 1”, 1-1/4”, 1-1/2”, 2”	1/4”, 3/8”, 1/2”, 3/4”, 1”, 1-1/4”, 1-1/2”
Thread options	NPT, BSPP, BSPT, JIC, ORFS, metric	NPT, BSPP, BSPT, JIC, ORFS, metric
Dominant markets	Global; US, Japan, Korea, China	Europe, Commonwealth, Middle East, Africa
Common machinery	Hydraulic power units, machine tools, presses, mobile equipment	Tractors, agricultural implements, construction equipment, European OEM machines
Interchange families	Parker 6600, Faster Series A (ANV/ASV), Stucchi Series A (IR-A), Eaton (Aeroquip) Series A	Stucchi IRB, DNP HNV, Faster Series B (NBV/NBVF), Eaton (Aeroquip) Series B

⚠️ The brand series listed above are interchange families used for identification. Always confirm the exact profile against a drawing or a physical sample before purchasing — “compatible” does not mean every vendor part is identical.

Why the Sleeve Profile Looks the Same But Isn’t

Both profiles use the same operating principle: slide the sleeve back, push the halves together, release — the locking balls drop into the groove and the poppets open.

The difference is the exact geometry of the locking groove, the plug nose and the seal area. Series B parts are dimensioned so the two halves seal with an O-ring on the male plug; Series A parts use a seal arrangement that is not interchangeable with B. The standard publishes the critical dimensions (ISO 7241-1 tables) so that any manufacturer making to the standard produces parts that mate — but only within the same series.

This is the reason a Series A plug will sometimes feel like it “almost” fits a Series B socket: the ball groove is close but not aligned, forcing the sleeve, and the seal does not seat. Forcing it damages the sleeve and the balls.

How to Tell Them Apart in 60 Seconds

From the part number. The family is usually encoded: “6600” or “6601/6602” → Series A (Parker-style); “IRB” or “HNV” → Series B. If the part number contains “A” or “B” after the series designation, that letter usually refers to the ISO profile — but not always, so read the datasheet.

From the plug nose. Compare the male half against the reference drawings. The most reliable field check is the dimension of the plug nose and the position of the locking groove — measure with a caliper and compare with the ISO 7241-1 profile tables for Series A and Series B at your nominal size.

From the socket. A Series B female will have the valve/poppet assembly positioned so the plug nose seats deeper; Series A sockets are shallower at the same nominal size. Again — measure, don’t guess.

From the supplier. A good supplier asks you two questions: what does the machine label say (Parker 6600? Stucchi IRB?), and can you send a photo or drawing of the existing half. If your supplier doesn’t ask, be careful.

Interchange Families Reference (Real-World Series)

The table below lists well-known commercial series that are built to each profile. It is a starting point for identification — verify with drawings before ordering.

Profile	Known interchange families
ISO 7241-1 Series A	Parker 6600/6601/6602, Faster ANV/ASV, Stucchi IR-A, Eaton (Aeroquip) Series A, CEJN 310/510, Dixon “ISO-A”
ISO 7241-1 Series B	Stucchi IRB, DNP HNV, Faster NBV/NBVF, Eaton (Aeroquip) Series B, Holmbury “Euro” profile, Dixon “ISO-B”

These references are compiled from public manufacturer interchange charts (e.g. the cosmic interchange guide and distributor cross-reference tables) and are offered as identification aids, not as a compatibility guarantee for any specific part number.

Which One Should You Stock?

Choose Series A if: your customers are hydraulic power units, presses, machine tools, construction machinery built outside Europe, or any fleet that already runs Parker 6600-style couplings. Series A is the largest installed base worldwide.

Choose Series B if: your customers run European tractors and implements (the ISO 5675 agricultural coupling is different again — do not mix), European excavators and telehandlers, or equipment whose OEM parts lists show IRB/HNV-style numbers.

Stock both. Most quick-coupling suppliers carry both profiles for the simple reason that both installed bases exist and neither is going away. The sizes that sell fastest are 1/2” and 3/8” in both profiles, followed by 3/4” and 1/4”.

Common Ordering Mistakes (and the Fix)

Mistake	Fix
Ordering “ISO 7241” without a profile letter	Always write “ISO 7241-1 Series A” or “Series B” on the PO
Assuming brand X “ISO-A” fits brand Y “ISO-A”	Within a profile, standard-compliant parts should mate — but verify the exact part, some brands make “near-standard” variants
Mixing A male with B female to “test”	They are not meant to mate; forcing damages the sleeve
Buying only male halves	Order matched male + female pairs with seals; spare seal kits separately
Ignoring the thread type	The ISO profile defines the coupling face, not the threads. NPT vs BSPP mismatch is the #1 reason “the right coupling doesn’t fit the hose”

What to Send Your Supplier

• Full part number of the existing coupling (both halves if possible)
• A clear photo of the male and female halves side by side
• The nominal size (1/4”, 3/8”, 1/2”, 3/4”, 1” …) and thread type needed (NPT/BSPP/BSPT/JIC/ORFS)
• Working pressure and flow of the circuit
• Whether it is for a new build or replacement of an existing coupling

FAQ

Can I convert a Series A system to Series B? Yes — replace the couplings on both the hose and the machine side. The threads stay the same; only the coupling face changes. Do it as a matched set.

Is Series B the same as the agricultural ISO 5675? No. ISO 5675 is a different standard (larger, free-flow poppet, tractor-to-implement). It is sometimes called “agricultural quick coupler” and is not interchangeable with ISO 7241 Series A or B.

Does “Parker 6600 compatible” mean identical? It means built to the same profile and intended to interchange. Dimensional tolerances can differ slightly between brands; for high-pressure or high-cycle circuits, confirm with the supplier.

Which profile is more common in China/Asia? Series A dominates the Asian industrial base (machine tools, power units, injection molding machines); Series B appears mainly on European-brand machinery sold into the region.

Can flat-face (ISO 16028) replace either series? Physically no — different face profile. But flat-face is the upgrade path for new builds where spill and contamination matter (see the ISO 16028 guide).

Ready to Confirm a Replacement?

Send us the part number or a photo of your existing coupling — we reply within 24 hours with the correct ISO 7241 Series A or Series B match, sizes, threads and lead time.