Each year the Masters (as well as the other Major Championships) gives out a contestant's pin for each competing golfer. This pin is used as the credentials for the player for that week. When attending the Masters, you'll often see these pins attached to the golfer's hat or belt during the week, as the pins give the players access to the front gate, locker rooms and other facilities not open to anyone else.
Presented here is the actual contestant's pin issued to Mark Calcavecchia for the 1996 Masters Tournament.