This pin comes from a framed set sold in 1998 at the Disneyland Resort. The set was entitled "The Atomic Age: Tomorrowland 1955-1961". The entire set consisted of 10 pins, which inludes this large oversize main pin, a title pin, and 8 pins that were also part of the 1998 attraction series, Flying Saucers, Spaceman K-7, Skyway, Phantom Boats, Viewliner, Autopia, Submarine Voyage, and Astrojets. The difference is that all the pins in this set are individually numbered XXX/750. The regular edition size was 750 sets, but there were also 75 Artist's Proof Sets, making the total 825. These sets can be denoted by no number preceding the /750.