This autographed jersey has been personally hand-signed by Jason Giambi of the New York Yankees. This autograph is certified by PSA/DNA (Professional Sports Authenticators). It comes with the numbered authentication hologram which can be verified on the PSA website, psacard.com. On October 23rd, 2023 PSA made an announcement that they will no longer be issuing COA cards to match the holograms. If an item authenticated by PSA does not come with a COA card, it is still considered fully authenticated.

Custom on-field style jerseys are a more affordable option for autograph seekers. These jerseys do not have any brand name or tags and are made in the Philippines. They feature stitched on names and numbers and are made to look very similar to the on-field jerseys that the players wear. These custom jerseys are very commonly used in the memorabilia industry.