A long size : 32mm X 11mm X height 20mm width Second, the main chip : LM393, infrared on the radio head Third, the working voltage : DC 5 V Four characteristics: 1, with a signal output instruction . 2, a single channel output . 3, the output valid signal is low . 4 , the sensitivity is not adjustable. 5 , can be used for parts counting, motor speed . . . . 6 , the circuit board output switch !