The 65966 is a versatile clamp-on lockout device designed to secure single-pole circuit breakers. It is constructed from rugged polypropylene and impact-modified nylon, featuring a thumbscrew design that clamps securely onto the switch tongue. A cover then locks over the thumbscrew to prevent it from being loosened. The device accepts lock shackles up to 9/32" (7.1mm) in diameter and includes detachable cleats to expand its range of applicable breakers. This lockout is ideal for use in industrial lockout/tagout (LOTO) safety programs to ensure electrical sources are isolated during maintenance.