The Universal 120-277V Breaker Lockouts are hinged with locking post design. Breaker lockout locks lever in off position to isolate and to prevent the use of breaker. It features a universal model that has unique screw clamp to lockout all Single-Pole Breakers. The Universal 120-277V Breaker Lockouts use thumbscrew to clamp lockout securely on to switch tongue, then pull cover over thumbscrew and lock in place to prevent clamp from being loosened. The new blade design also provides a tighter grip with less torque on thumbscrew. Breaker lockout meets RoHS standards.