Non-drift silicon light sensor with IR filter. DC relay with zero-crossing circuitry for extended life. 15 year design life. Conformal coated PCB. Exceeds 10000 ON/OFF switching cycles. Ideal for single or multi-fixture HID and LED installations (up to 1650 W @ 277 V AC). 255J MOV surge protection element. 1/2 inch-14 NPSM threaded stem fits standard outlet boxes and wall packs.