2.25" with metal back and bar pin which caused a raised bump on the front over the letter "E" of "Space." Full inscription is "I Scored With Space Invaders." This button was likely released in 1980 to promote the release of "Space Invaders" on the Atari 2600 game system at that time. A scarce and historic promotional button from the era which saw the video game industry expand from a novelty to a global business. Only example we've seen.