Ground fault circuit interrupter [GFCI] senses when it is miswired. Reset button lock-out function protects from circuitry damage due to disabling voltage surge spikes. Use when a receptacle is needed close to pipes or water. Includes a cover. Indicator light provides quick visual reference of a tripped condition. Use on overcurrent protected 15 amp or 20 amp, 120 volt AC grounded two-wire branch circuits. 1 per pack.