12-RB3
The 12-RB3 discharges 3   .60 Cal rubber ball.  The 60 durometer rubber ball can be skip fired at closer ranges and direct fired at longer ranges. 

12-RB18
The 12-RB18 discharges 18 .32 Cal rubber balls.  The 80 durometer rubber balls can be skip fired at closer ranges and direct fired at longer ranges. 

12-RB18HV
The 12-RB18HV discharges 18 .32 Cal rubber balls at a higher velocity than the standard 12-RB18 cartridge for extended range.  The 80 durometer rubber balls can be skip fired at closer ranges and direct fired at longer ranges.