Google - what info Google wants for ALL products
Basically, Google wants the following information on all products.
BRAND
MANUFACTURER-PART-NUMBER
Google calls this combination of data the Unique Product Identifier
For some products, Google requires an actual UPC code or an ISBN number instead of just a Manufacturer-Part-Number. Google calls these extra numbers GTIN. If you are a merchant and you sell products where BRAND and Manufacturer-part-number info is normally available, you must include it. If you sell CUSTOM MADE or one-of-a-kind items where no manufacturer part number or brand even exists, then you must use the "identifier exists" field and mark it FALSE.