Designed to meet UL 943 Standard, SmartlockPro® Self-Test GFCI includes auto-monitoring feature which conducts internal test to ensure that it is providing protection from ground faults. If self-test detects any condition that would indicate GFCI protection might be compromised, visual LED indicator provides alert by switching from green to red and GFCI may be automatically tripped. Reset/Lockout feature provides added level of safety by preventing reset if device cannot respond to ground fault.