MP-40-RB6
The MP-40-RB6 discharges 24 .60 Cal rubber ball.  The 60 durometer rubber ball can be skip fired at closer ranges and direct fired at longer ranges. 

MP-40-RB3
The MP-40-RB3 discharges 150 .32 Cal rubber balls.  The 80 durometer rubber balls can be skip fired at closer ranges and direct fired at longer ranges.