Master Lock S3823 Grip Tightâ„¢ Plus Circuit Breaker Lockout Device fits Oversized Handle Circuit Breakers (480/600 V). Its lightweight, one-piece design easily and consistently installs without use of tools. The stainless steel thumbscrew and curved blade provide a tight grip on the circuit breaker handle so device remains secure. A fold-down cleat provides enhanced switch throw blocking when needed. Compatible with a wide variety of circuit breaker handle shapes and sizes.