Method

How we verify an equivalent.

A cross-reference is a claim. This page is the standard every claim on this site has to meet before we publish it.

The rule that governs everything

We never assert a bare equivalence. Every result is a match plus the spec differences, plus a classification, plus the caveats, plusthe source — or an honest “we can’t verify this.” A tool that confidently returns wrong equivalents is worse than no tool.

The four verdicts

• Drop-in. The interface dimensions match a shared ISO standard and the functional specs are within tolerance. We still tell you what to double-check (port thread, seal, medium).
• Equivalent — with changes. Functionally equivalent, but you need a named change: an adapter, a thread variant, a seal swap, a minor dimensional allowance.
• Application-dependent. Whether it works depends on your duty cycle, medium, or temperature. We ask the qualifying question instead of guessing.
• Can’t verify.The data doesn’t support a confident match — a catalog gap, a proprietary interface, or conflicting sources. We say so and route you to a person. We never fabricate.

When we refuse to answer

A result is automatically downgraded or withheld when: the spec data is incomplete on either side; the sources conflict; the interface is proprietary with no dimensional match; or you’ve told us the application is safety-critical and any material difference exists. For safety-critical applications we always route to review rather than return an automated verdict.

Where the answers come from

Published manufacturer catalogs, international standards (ISO interface dimensions), and documented sizing physics. Every published spec cites its source — the catalog and the date we read it. Rules and dimensional matching do the deciding; language models only explain and add caveats. Software may never upgrade a verdict — it can only explain it, caveat it, or downgrade it. That is a structural guarantee, not a policy.

What “specimen” means

While a section is in build, layout examples are marked Specimen. A specimen card demonstrates the format — it is not verified data and we label it so you never have to guess which is which. Specimen cards are replaced with cited, verified cross-references before a section launches.

Independence

The reference content on this site is free and complete whether or not you ever request a quote through us. How we make money is disclosed plainly on the About page.