Miniature light barriers, W4S-3, WTB4S-3P3261, switching distance max.: 4 mm ... 180 mm, sensor principle: reflection light sensor, detection principle: background suppression, switching output: PNP, switching type: light/dark switching, connection type: cable with connector M8, 4-pin, 150 mm, light transmitter: PinPoint LED, setting: potentiometer, communication interface: -