4 Digital LED Tachometer RPM Speed Meter +Hall Proximity Switch Sensor NPN 8-24V Product Feature 100% brand new and high quality. 4-digits display, clear and easy for readings. Mini size, high performance and fast reaction speed. With good stability, high accuracy, anti-interference ability. Using the latest A/D conversion chip, high stability reference IC and stick chip components. It can be applied to voltage and current measurement, also can be an external sensor to measure temperature, pressure, displacement and other physical quantities. Setting parameters will be memorized when power off. Suitable for detecting the speed of every kind of motors. Over-range display: the thousand unit display "1" or "-1", the last three do not show. Product Specification Display type：LED display Voltage：DC8-24V Current：30mA Measurement range：10-9999rpm Accuracy：0.1% Clear zero time：About 10s Display refresh rate：>3 times/sec Size：about 80*25*40mm(L*W*H) Installation size：about 76*39mm LED color：red/blue Detected objects：Magnet. Detection range：1mm-10mm. Proximity output current：20mA(For the sensor). Operating temperature：-10 to 60°C. Sensor size：60 x 10mm Sensor wire length：1.2M Magnet：10x2mm Package Included 1 x LED Tachometer 1 x NPN hall proximity sensor 1 x Magnet