Capcom 's Play System 2 (CPS2) first appeared in 1993 with the release of Super Street Fighter II. The system consists of a motherboard (A board) which snaps together with the game board (B board).

The A & B boards are colour coded for specific areas  -  Japan, Asia, the US / Europe and Spain.

Green and blue A & B boards can be interchanged. The grey and orange A & B boards are also swappable with each other but not with green or blue ones. For further information see Chris Mullins excellent CPS2 FAQ.