The Twist-lock Photocontrol features a 3 PIN design that complies with the ANSI C136.10 standard interface. It can be inserted directly into a 3-pin socket (NEMA type receptacle), allowing users to Clockwise install and reverse-wise this easily and without the risk of power failure. This greatly improves maintenance convenience. Various types of optical controller are available, including CDS photoresistor sensors, IR-filtered phototransistors, ordinary phototransistors and silicon photodiodes, to meet different light sensing needs.