Pedro Martinez has autographed this official Boston jersey. Jersey is a size M and comes with the 2004 World Series patch. He also wrote 2004 WS CHAMPS for winning that World Series. Autograph was witnessed and is authenticated by James Spence Authentication (JSA). Comes with their unique sticker # on the item and COA which is verified on their website. JSA is one of the world's leading authenticators of sports autographs.