Parker A-LOK® Cross-Reference: Crestflo Equivalents in Stainless AND Exotic Alloys

Reviewed by the Crestflo Engineering Team

> Trademark & independence notice: "A-LOK®" and "CPI™" are trademarks owned by Parker Hannifin Corporation. Crestflo is not affiliated with, authorized by, sponsored by, or endorsed by Parker Hannifin. Every reference on this page is nominative. It exists only to identify the parts you already know, so you can locate the dimensionally equivalent Crestflo fitting. The claims made here are factual and dimensional in nature. Crestflo supplies independently manufactured equivalents, not genuine Parker A-LOK products.

Match your Parker A-LOK® part to a Crestflo equivalent

Crestflo makes dimensional equivalents to Parker A-LOK® tube fittings. These are twin-ferrule (two-ferrule) instrumentation compression fittings, tested to ASTM F1387, available in 316 stainless and exotic alloys such as Hastelloy, Super Duplex, Inconel, and Monel. Delivery runs 6-8 weeks. Give us the Parker A-LOK part numbers you're buying now, and we'll send back the interchange equivalent, the alloys it comes in, and a quote.

Send a print or a sample, and we'll find the equivalent for you.

Request your Parker A-LOK cross-reference & quote →

Scope: Crestflo compression tube fittings are instrumentation-grade fluid-system parts made from stainless steel and alloy. They're not plumbing fittings, nor copper compression fittings. Here, "ferrule" means a fluid-system compression ferrule, not an electrical wire ferrule.

Designations & related terms

This page has one reference block. Search by whatever term you use, and every entry leads back to the same interchange.

What Parker A-LOK tube fittings are

Parker A-LOK® tube fittings are twin-ferrule (two-ferrule) instrumentation compression fittings, built to seal small-bore stainless and alloy tubing in analytical, process, and hydraulic systems. A complete fitting comes down to four parts: a body, a nut, a front ferrule, and a back ferrule. Tighten the nut, and the two ferrules bite onto the tube OD, forming a gas-tight, mechanically gripped joint. Within Parker Hannifin's Instrumentation Products line, A-LOK sits next to CPI™, the company's single-ferrule design. These aren't two names for the same fitting; they're distinct sealing systems. Buyers recognize Parker's ordering-code pattern on part markings and line cards. Crestflo builds to that same two-ferrule geometry and the same size conventions, and that's exactly what makes a location-for-location swap possible. For the design distinction, see single vs double ferrule.

Parker A-LOK cross-reference: how to find your Crestflo equivalent

A cross-reference answers one question: for the Parker A-LOK part you buy today, which Crestflo part interchanges dimensionally, and in what alloys? Part-number mapping can't be guessed. It has to be verified against your exact series, size, and material. That's why Crestflo builds your cross-reference to order instead of publishing a generic parts table. Every equivalent stays accurate to your bill of materials.

Parker A-LOK part number cross reference: how to request it

Send along the Parker A-LOK part numbers, a line-card export, a drawing, or even a physical sample. The Crestflo Engineering Team takes it from there. Back comes the interchange equivalent, ferrule and connection parity notes, available alloys, and a quote. There's no login, no gated tool to wrestle with.

Request your Parker A-LOK® cross-reference →

Parker A-LOK cross-reference chart / PDF: what you get instead

Competitors bury interchange data in gated tools or PDFs you can't even search. Crestflo hands your chart back as a clean, verified document, tied directly to your actual part list. Request one through the request-a-quote form, or just email sales@crestflousa.com.

Parker A-LOK 316 / stainless equivalent

Crestflo's core interchange runs on 316 stainless A-LOK lines. Every equivalent ships as standard in 316/316L. 904L and the full alloy range below aren't stocked as default, but they're available on request.

Parker A-LOK vs CPI: twin-ferrule vs single-ferrule

If your part is actually CPI™, Parker's single-ferrule design, it interchanges to a Crestflo single-ferrule fitting, not the twin-ferrule A-LOK equivalent. The geometry just isn't the same. Crestflo makes both types, though. Check the Parker CPI cross-reference and single vs double ferrule pages to confirm which design you're actually running.

The wedge: Parker A-LOK equivalents in stainless AND exotic alloys

Crestflo stands apart from stainless-only cross-references here. The same dimensionally equivalent fitting isn't limited to 316 SS; it's also offered across exotic and corrosion-resistant alloys. Availability depends on fitting type and alloy, so confirm per-part details with your quote.

Alloy-availability matrix, Crestflo Parker A-LOK-equivalent fittings

✓ marks what's available, or made-to-order, in that particular alloy. Standard items ship from ready stock. Specials get made to order, with delivery running six to eight weeks. We'll confirm the alloy for each part when we send your quote.

Parker A-LOK tube fitting in Hastelloy C-276

In wet-chlorine, sulfuric, and mixed-acid service, Crestflo matches the A-LOK fitting in Hastelloy C-276 / C-22 step for step. For details, see Hastelloy C-276 tube fittings and the Hastelloy C-276 material page.

Parker A-LOK tube fitting in Super Duplex 2507

Offshore and high-chloride seawater service calls for something tougher: Super Duplex 2507 fills that role. You'll find the fittings at Super Duplex 2507 tube fittings, and full specifications sit on the material page.

Parker A-LOK tube fitting in Inconel 625 / Incoloy 825

When it comes to high-temperature and sour-gas service, Crestflo matches it in Inconel 625 and Incoloy/Inconel 825. Check out Inconel 625 tube fittings and Inconel 825 tube fittings.

Parker A-LOK tube fitting in Monel 400

For hydrofluoric acid and marine applications, the equivalent material is Monel 400. See Monel 400 tube fittings and the material page.

Parker A-LOK tube fitting in 254 SMO, Alloy 20 & 904L

For sulfuric-acid and high-chloride process lines, Crestflo also builds the equivalent in 254 SMO, Alloy 20, and 904L. Details live on the 254 SMO, Alloy 20, and 904L material pages. Sour service is a different case: the equivalent there is built to NACE MR0175 / ISO 15156. Both standards are covered on the NACE MR0175 and ISO 15156 pages.

Why the interchange is proven: ASTM F1387

Crestflo compression tube fittings aren't an interchange claim built on marketing language. They're tested to ASTM F1387, the performance qualification standard for mechanically attached fittings. That standard covers the dimensional and performance behavior that actually forms the basis for equivalence. There's a real gap between a documented, qualified equivalent and some uncontrolled marketplace listing calling itself "equivalent" with no proof and no traceability behind it. For more detail, see the ASTM F1387 interchange qualification page.

Interchange-proof summary

Values per applicable standard; customizable to requirement.

Interchange vs. intermix: the honest engineering note

This is the question every specifying engineer ought to ask. The honest answer is the one that earns trust.

• Interchange (correct): swap out a complete Parker A-LOK fitting for a complete Crestflo fitting at the same spot. The body, the nut, both ferrules, all Crestflo. That's the whole idea behind "Parker A-LOK equivalent" and "drop-in replacement" here.
• Intermix (don't do this): putting a Crestflo ferrule or nut with a Parker body, or the reverse, inside one joint. Ferrule geometry and hardness are engineered together as a set. Mix brands within a single joint and you risk the seal; that's not what "interchange" means, and it never will be.

When buyers search "Parker A-LOK compatible fittings" or ask "is X compatible with A-LOK," the precise answer is this: use complete Crestflo fittings as interchange equivalents. Don't mix components from different sources within a single joint. Crestflo relies on the terms "interchange" and "equivalent," never "compatible" or "intermix." The distinction is a safety fact, not a word game.

Why buyers switch to Crestflo

Crestflo functions as an alloy-aware alternate source to Parker A-LOK. Buyers don't switch for vague reasons; they switch for specific ones:

• Drop-in replacement, dimensionally equal and backed by ASTM F1387, not a marketplace guess.
• Stainless and exotic alloys: Hastelloy, Super Duplex, Inconel, Monel, 254 SMO, Alloy 20. That's a lineup most stainless-only cross-references simply don't offer.
• 6-8 week delivery, well ahead of the long lead times typical of specials from the major suppliers. It's a genuine answer to "Parker A-LOK long lead time alternative."
• Cost-competitive even after US duties/tariffs.
• Small MOQ and private-label / OEM programs, a genuine second-source and dual-sourcing option.
• Heat/lot number on every part with EN 10204 3.1 MTC as standard.
• ISO 9001 / 14001 / 45001 & PED certified.

Crestflo is the instrumentation division of an export house that's been running for four decades and carries formal recognition from the Government of India. It has a proven delivery track record across the Middle East. Behind the brand sits real manufacturing heritage, now sharpened into a instrumentation line built specifically to serve US customers. Origin: Indian. US and European melt is available on request, and every order comes with full material traceability. We Engineer Confidence.

Explore the underlying product line: Crestflo tube fittings and nut & ferrule sets.

Fitting types, threads and geometry we equal

Unions, tees, elbows, crosses, reducers

Crestflo covers the entire body catalog: union, tee, elbow, cross, and reducer, both straight and reducing.

Male / female connectors, adapters, port connectors, bulkheads

Thread and adapter ends are covered here too: male connector, female connector, tube adapters, port connector, and bulkhead union. As for thread options, you've got NPT, NPTF, BSPT, BSPP, ISO parallel, JIC-37°, and SAE-ORB to choose from.

Caps, plugs, nuts and ferrules

Cap, plug, and nut & ferrule sets handle line termination and sealing. Each one ships as a complete Crestflo set. Front ferrule, back ferrule, and nut are engineered together, as a single unit. Order them that way too. Don't mix components from different sets.

Metric and imperial size parity

Crestflo builds every equivalent in both imperial (fractional) and metric tube OD up to 2" (50 mm). That's why a "Parker A-LOK metric tube fitting equivalent" counts as a direct request, not some conversion exercise.

How to request your Parker A-LOK cross-reference

1. Send your Parker A-LOK part numbers, a line-card export, a drawing, or a sample.
2. Tell us the alloy and size you need, or ask us to match what you already run. Let us know as well whether the part is A-LOK (twin-ferrule) or CPI (single-ferrule).
3. We return the Crestflo equivalent, alloy availability, and quote, typically for delivery in 6–8 weeks.

Buyer paths vary by who's asking. Distributors go through the line-card or stocking program. Equipment manufacturers send a print for made-to-print interchange. OEMs get the private-label program. End users, MRO, and EPC customers submit an RFQ or request a sample. Every path leads back to the same place: the RFQ form.

RFQ form fields: Name, company name, email, phone number, and a description of the requirement.

Request your Parker A-LOK® cross-reference & quote → · Or contact Crestflo: sales@crestflousa.com · +1 346 594 9005 · Houston, TX.

Other brand tube-fitting cross-references

Don't work with Parker A-LOK fittings? Crestflo publishes interchange guides spanning the instrumentation category:

• Parker CPI cross-reference, A-LOK's single-ferrule sibling
• Swagelok cross-reference: start here for a Parker A-LOK vs Swagelok comparison, or when you need a Swagelok to Parker A-LOK / A-LOK equivalent Swagelok interchange
• Hy-Lok cross-reference · Fitok cross-reference
• Hoke cross-reference · Gyrolok cross-reference
• DK-Lok cross-reference · Superlok cross-reference
• All brand interchange guides · Master interchange chart

Related: Parker A-LOK alternative · Parker A-LOK vs Crestflo.

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