This Master Lock Miniature Circuit Breaker Lockout fits most miniature ISO/DIN pin-out circuit breakers to help prevent accidental engagement of electrical circuits during maintenance. The device fits breakers with standard toggle openings 7/16” (11mm) or less -- a black tab signifies a standard toggle. Compatible with Master Lock and American Lock safety padlocks and most lockout hasps (all sold separately). Ideal for most miniature ISO/DIN circuit breakers or as part of a comprehensive OSH-compliant lockout/tagout safety program. Mini Circuit Breaker LO, Pin-Out, Standard