Master Lock Grip Tight circuit breaker lock outs not only have a narrow profile for side-by-side lock out, they also have a secure and simple mounting for a solid lock out. The body is made from hardened steel. Master Lock Grip Tight circuit breaker lockouts not only have a narrow profile for side-by-side lock out, they also have a secure and simple mounting for a solid lock out. The body is made from hardened steel.The Lockout Griptight Set comprisess:MLK491B, suitable for wide and tall breaker toggles.MLK493B, suitable for standard breaker toggles.