Leviton SmartlockPro GFCIs are designed to meet the latest UL standard for auto-monitoring self-test. Our complete line of self-test GFCIs periodically conducts an automatic internal test to confirm that it can respond to a ground fault. With the slimmest profile on the market the device allows for fast and easy installation while Leviton’s patented reset lockout mechanism prevents reset of the GFCI if it is Not wired or operating correctly.