Slot Sensors also called as Fork Switches because of their forked shape, detect objects that pass between the two arms one is the Transmitter & the other is the Receiver. These sensors operate on a through beam design, they combine the transmitter & receiver into a fixed housing so alignment is never an issue. The transmitter emits pulsed light in the infrared wavelength range. The receiver detects the light beam and immediately converts a beam interruption caused by an object in the sensing zone into a switched signal. Fork Width is defined as the height between the transmitter & receiver. Depth is defined as the distance between the transmitter & receiver area and back of the opening.