About half the size of most standard photoelectric switches, these fit comfortably in tight spaces. The transmitter and receiver are built into the housing, so you don’t need to align components or measure sensing distance to install them. These are receiver switches, which detect objects moving at high speeds as they interrupt the light between the transmitter and receiver. Also known as slot sensors, these fork switches have a receiver and transmitter that directly face each other. Keep in mind that because these switches are one piece, they’ll only work with components that fit between the transmitter and receiver. They produce PNP or NPN signal output; to determine the signal output of a switch you are replacing, use Testers for Proximity and Photoelectric Switches (not included). Choose the mounting orientation that best suits your process.