Check the listing for details. 2 PCs NPN Inductive Proximity Sensor Detection Switch NO DC 10-30V SN04-N 4mm. Condition: New. Listed at 12.00 USD. US Seller Product Feature:Characterized by DC 3 wire type, NPN, NO output type, 0-30V DC working voltage, when proximity switch is close to some target object, it will send out control signal.Used widely in the machine tool industry, frequency counters and other automatic control system, etc. Product NameProximity Switch SensorModelSN04-NWire TypeDC 3 Wire Type (Brown, Black, Blue)TheoryInductance SensorOutput TypeNPN, NOOutputSwitching TransducerSensing Distance4mmWorking Voltage10-30V DCResponse Frequency500Hz maxIndicatorRed LEDSize36 x 18 x 18mm / 1.4" x 0.7" x 0.7" (L*W*H)Cable Length (Approx.)110cm / 43.3"Hole Size0.9 x 0.4cm / 0.35" x 0.2" (L*W)Extenal MaterialABS ResinNet Weight34gColorBlack, Blue Package Includes:2 PCs Sensor4 Screws and 4 nuts