Small light barriers, W9, WTB9-3P3461, switching distance max.: 20 mm ... 350 mm, sensor principle: reflection light sensor, detection principle: background suppression, switching output: PNP, switching type: light/dark switching, connection type: cable with M12 connector, 4-pin, 120 mm, light transmitter: PinPoint LED, setting: potentiometer, communication interface: -