1597BK. Self-test GFCI RECEP 15a 125V 20a F bk . Conducts an automatic test every three seconds, ensuring its always ready to protect. 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.. thinner than competitors GFCI receptacles: leaves more room for wires in the box. . Auto-ground clip assures a positive ground to metal box. . Meets 2015 UL requirements. . Feed-thru wiring configuration allows GFCI to protect downstream receptacles. .