All Prinzing circuit breaker lockouts are made of durable polycarbonate material and are quick and easy to apply. Single Pole Breaker Lockout (BL01) is designed to fit most single-pole breaker applications. Multi-Pole Breaker Lockout (BL03) is designed to fit multi-pole breakers. "No Hole" Circuit Breaker Lockout (BL04) is designed to fit circuit breaker toggles up to 1/2" wide without a recess hole in the toggle. 3-Phase Breaker Lockout is designed to lockout a wide range of three-phase breaker handles up to .8" thick and 3" wide.