2 pcs Inductive Proximity Switch: 1 pcs LJ18A3-8-Z/BX 8mm & 1 pcs LJ12A3-4-Z/BY 4mm It is a component widely used in automatic control industry for detecting, controlling, and noncontact switching. When proximity switch is close to some target object, it will send out control signal. It's widely used in machine, paper making, light industry for limiting station, orientation taking count, speeding trial ect. Metal shell, DC type, 4mm detecting distance, 3 wire system.Power supply inverted connecting protection, short circuit protection, non-contact detecting device. Product Name: Inductive Proximity Switch; Theory: Inductive Type Sensor Model: LJ18A3-8-Z/BX & LJ12A3-4-Z/BY Switch Appearance Type: Cylinder Type Wire Type: DC 3 Wire Type (Black, Brown, Blue); Output Type: PNP, NO; Detect Object: Iron Current Output: 300mA; Supply Voltage: DC 6-36V; External Material: Plastic, Metal Color: picture color Diameter of Head: 18mm / 12mm Detecting Distance: 8mm/ 4mm Cable Length: 1.1M/43.3 inch Package Content: 2 x Inductive Proximity Switch