Have good stability, high measurement precision.Strong anti-jamming capability.Setting parameters will be memorized when power off.With a standard size, easy to install.Suitable for detecting the speed of every kind of motors.Specifications:Power requirement: DC 8-24VMeasure range: 10 ~ 9999RPMError range: 0.1%Clear zero: AutomaticClear zero time: About 10sRefresh frequency: 0.2-0.5S(120-1200RPM),0.25-0.06S(2400-9999RPM)Response frequency: 100HZ.Measure indication: (RPM Less than 5000,2),(RPM more than the 5000,3)Sign: NPN 5 wires normally open.Display: 5 x 2cm LEDDetection range: 1mm-10mm.Proximity output current: 20mA(For the sensor)Operating temperature: -10 to 50 CelsiusSensor wiring: brown(Power+), black(Test+),blue(signal)Colour:blackMaterial:plasticPackage Contents:1 * Tachometer RPM Speed Meter1 * Hall Proximity Switch Sensor NPNOnly the above package content, other products are not included.Note: Light 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.