An offer to transfer some rights to an item or to provide a service — for example, an offer to sell tickets to an event, to rent the DVD of a movie, to stream a TV show over the internet, to repair a motorcycle, or to loan a book.<br/><br/> For <a href="http://www.gs1.org/barcodes/technical/idkeys/gtin">GTIN</a>-related fields, see <a href="http://www.gs1.org/barcodes/support/check_digit_calculator">Check Digit calculator</a> and <a href="http://www.gs1us.org/resources/standards/gtin-validation-guide">validation guide</a> from <a href="http://www.gs1.org/">GS1</a>.