This is a replacement optical wheel for a 4.5" Atari trackball used in several Atari arcade games from the 1980s.  These include Missile Command, Football, Baseball, Basketball, Soccer. There are two versions of the wheel.  The original trackballs use a 36 post wheel for both axes.  So if you want the original experience use the 36 post version.  I also included a 52 post version that will make the trackball more responsive. This has been tested in Missile Command and works very well to improve the responsiveness and acceleration of the cursor.  I tested several versions with other numbers of posts and found that the 52 post version works the best.  

I suggest slicing with .2mm layers and 20% infill. PLA and PETG work well.