4.5″ Atari Trackball Ball Bearing kit (SET of 5pcs) (MP1139). These fit and are used on all Atari 4 1/2″ inch trackballs and used on Missile command (upright), Atari Football, Atari Basketball, Atari Baseball, Atari Soccer, Some steering wheel controls and Sega UFO Catcher (12 bearings need per claw) and anywhere you need this size of bearing. Atari original part number is 033367-01, and they are 0.875 x 0.375 x 0.2187 inches in size. Original and replacement bearings were only ABEC 3 rated or less and our bearings are THE BEST top of the line bearing that we had made and are ABEC 5 precision rated and are greased and we recommend using a high quality bearing oil on them. These Ball bearings are a high-precision premium quality open R6 type bearing. Don’t settle for all those other supplier’s lower grade bearings because you will feel the difference in your arcade game play and see the difference in how long they last because we didn’t settle for okay but THE ABSOLUTE BEST. For every quantity of 1 added to your cart you will receive 5 bearings.