Superstar Signatures is an insert set in 2008 SPX. This 15-card set features signatures of some of baseball's biggest stars. The cards were randomly inserted into packs. Derek Jeter did not return his stickers in time for pack out, so a redemption card was packed in its place. It can be exchanged until 4/28/2010. The set was also paralleled with a Silver set that was randomly inserted into the box topper packs.