LEGRAND GFCI Duplex Receptacle 15Amp Tamper Resistant 1597TRW0 - WHITE Conducts an automatic test every three seconds, ensuring it's 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 Shutter mechanism inside the receptacle blocks access to the contacts unless a two-prong plug is inserted, helping ensure hairpins, keys, etc., will be locked out Thinner than competitors' GFCI Receptacles: leaves more room for wires in the box Feed-thru wiring configuration allows GFCI to protect downstream receptacles Prevents line-load reversal miswire: no power to the face or downstream receptacles if wired incorrectly