The Binary Firing System GEN 3 (BFSIII) is a 3-position trigger. In position 3, it fires one round on pull and one round on release. This trigger is ideal for having more fun than you thought was possible with your Ruger PC Charger and Ruger PC Carbine. Release round can be canceled by simply moving our Patent Pending selector out of Binary mode while holding the trigger back.Position 1: Safe, Will not firePosition 2: Semi, Fires 1 round per pullPosition 3: Binary, Fires 1 round on pull and 1 round on release