The Mater Lock No. 491B Grip Tight™ Circuit Breaker Lockout Device fits wide or tall breaker toggles typically found on hi-voltage/hi-amperage breakers. The innovative patented Grip Tight™ design effectively locks out circuit breakers with a simple thumb turn and then close clamping handle for a tight grip on the toggle. Device accepts all American Lock® and Master Lock® safety padlocks and most lockout hasps for full lockout. Durable construction stands up in harsh environments and compact design is easy to carry and store.