This IN-LINE 15A RATED UL AUTO-RESET GFCI is an EASY User assemble REPLACEMENT GFCI device. This is the NEWEST version with BUILT IN SELF-MONITORING feature per the latest UL GFCI Standards. AUTO- REST simply means if you have a temporary loss of power, the unit will automatically reset when power is restored. Great feature to make sure your equipment is then protected and is fully functioning again when power is restored without you having to remember to reset the device.