Certified products are typically endorsed with a certification mark provided by the product certifier. Issuance of a certification mark is at the discretion of the individual product certifier. ISO Guide 65 does not require the product certifier to offer a certification mark in the event that a certificate is offered. When certification marks are issued and used on products, they are usually easy to see and enable users to track down the certification listings to determine the criteria that the product meets, and whether or not the listing is still active.