Legrand - Pass & Seymour 2097W TradeMaster 20 Amp 125V AC GFCI Duplex Receptacle, White Conducts an automatic test every three seconds If the device fails the test, the indicator light flashes to signal that the GFCI should be replaced It also has our proven SafeLock Protection feature: if critical components are damaged and protection is lost, power to the receptacle is disconnected