This trak-ball kit is used in Missile Command upright and cockpit versions as well as Atari Football (X's and O's) 2-player and 4-player models, Atari Basketball, Atari Baseball and Atari Soccer.  The kit includes the actual black trackball, two stainless steel encoder shafts and five oil lubed bearings. The trak-ball is a brand new OEM part made by the exact same manufacturer who made the original trak-ball for Atari over 25 years ago. Color, material, size and weight specifications are exact.