Round light barriers, GR18 Inox, GRTE18S-P2442V, switching distance max.: 5 mm ... 550 mm, sensor principle: reflection light sensor, detection principle: energetic, switching output: PNP, switching type: light/dark switching, connection type: connector M12, 4-pin, light transmitter: PinPoint LED, setting: potentiometer, communication interface: -, included in delivery: fastening nut (2 x)