This is a First Day Cover that has been hand signed by the great, Bob Feller & Warren Spahn. The cachet has been authenticated and slabbed by PSA/DNA. The serial number is verifiable online using PSA/DNA #84092274. The cover comes encapsulated in a tamper-proof cover. 100% authentic signature from Pittsburgh Pirates legend, Bob Feller & Warren Spahn. A great gift idea for a Pittsburgh Pirates or MLB collector.