The sensor tester is designed to test two-, three- or four-wire DC sensors with PNP or NPN outputs. Capable of testing inductive (metal induction), capacitive, optoelectronic, magnetic or ultrasonic. Sensor testers allow users to quickly and confidently check sensor operation, avoiding unnecessary replacements and adding fault-finding capabilities. The tester is portable and can only use 2 6F22 9V batteries (Battery Not Included) Application:Optoelectronic/Proximity/Magnetic/Fiber Amplifier Type:A:Without 2 x 9V Battery Colour:Black Material:Plastic Size:93x60x23mm Package Contents: 1 x Photoelectric Switch Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.