Why it matters
Mark up a hydraulic fitting with mpn, gtin, and additionalProperty for thread type and pressure rating, and an engine can answer "what is the MPN for a half-inch JIC swivel rated 5,000 psi." That is the difference between a part page an engine can parse and one it skips. Generic Product schema is documented everywhere. The industrial part is where catalogs go wrong: the spec data sits in a PDF or a description blob, not in machine-readable fields. Without mpn and additionalProperty, the engine sees a price and a title and nothing it can match against a buyer's spec query.
How to apply it to a SKU
Map the fields your buyers search on into named schema properties:
- mpn for the manufacturer part number, the string buyers paste in.
- gtin (or gtin13/gtin14) for the barcode, when you have one.
- additionalProperty entries (PropertyValue) for each spec: thread type, pressure rating, bore size, material.
- brand for the manufacturer, kept distinct from your distributor name.
In practice
A distributor selling a 1/2" JIC 37-degree swivel rated to 5,000 psi pulls those values straight from PIM rather than burying them in prose. The page emits Product with mpn set to the catalog number, plus additionalProperty for thread (JIC 37), pressure (5,000 psi), and size (1/2"), each as a PropertyValue with name and value. Run it through a structured-data test, confirm the fields parse, then check that the spec values match the PIM record exactly. Mismatched markup is worse than none.