What is a Unique Product Identifier
Google require you to provide an industry standard id for your products.�� You cannot generally use your Actinc / Sellerdeck product reference as your unique product reference for this field.
You unique product identifier can be one of the following
UPC - Universal Product Code � 12 numeric digits
EAN - European Article Number, typically 13 numeric digits
JAN - Japanese Article Number, Japan only, 8 or 13 digits
ISBN - International Standard Book Number, ISBN-10 or ISBN-13
GTIN (must be set to one of the above)
Brand and MPN (Manufacturers part number)
If you do not meet include a valid unique product identifier google will reject your product listings.
Exceptions
Two exceptions exist, items listed under the apparel and accessories category can be submitted with just a brand, secondly, custom goods can be exempted, if you make custom products that do not have a generally recognised identifier then you must set the Indentifier_exists property to true in your feed. �In the past you have been able to apply for exemption but that is no longer possible. � The identifier_exists property is available in the latest beta for the product mash.
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How to find your Unique Product Identifiers
If you don�t� know what you unique identifiers are then you can find find it on Google Shopping "Compare prices" pages, under the �technical specifications� section for Electronics items, the "Tracks" or "Details" section for Media, and the �Overview� section for books.
You can look up UPCs or EANs at the�Internet UPC Database website, which includes many, though not all product identifiers that have been issued. You can look up ISBNs at�ISBNdb.com. You can also checkISBN-13�on Google Shopping.�
More Info
You can find more details on Unique Product Identifiers in Google Shopping here :
http://support.google.com/merchants/bin/answer.py?hl=en&answer=160161
and also here :
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