Usain Bolt Hand Signed 2008 Beijing Olympics Replica Gold Medal. Auto has been authenticated by PSA DNA. PSA is one of the leading third party authentication companies in the world. PSA is considered to be one of the leading autograph authentication companies in today's autograph industry. With PSA you get fast and easy online confirmation of your item's certification number, along with increased value of your item.The PSA sticker is securely fastened onto your item, and the proprietary watermark is virtually impossible to replicate. When an item has been authenticated by PSA, you can feel confident that you are receiving a genuine 100% authentic signature.