Unique among baseball collectibles, the 1973 Topps Pin-Ups set was designed as a “test issue” and is never known to have been distributed to the public. The item was originally designed to wrap around rectangular bubblegum pieces. Comprised of 24 pieces, each thin, wax paper piece in this set measures 3-7/16” x 4-5/8” and carry gum-wrapper graphics on one side, and a colorful, featured-player "pin-up" on the reverse, along with a facsimile signature. The full set consists of Hank Aaron, Dick Allen, Johnny Bench, Steve Carlton, Nate Colbert, Willie Davis, Mike Epstein, Reggie Jackson, Harmon Killebrew, Mickey Lolich, Mike Marshall, Lee May, Willie McCovey, Bobby Murcer, Gaylord Perry, Lou Piniella, Brooks Robinson, Nolan Ryan, George Scott, Tom Seaver, Willie Stargell, Joe Torre, Billy Williams, and Carl Yastrzemski. The 1973 Topps Pin-Up set is among the toughest of all Topps Test issues to achieve in complete set form and are rarely offered on the secondary market.