Power requirement:DC 8-24V Measure range:10 ~ 9999RPM. Error range: 0.1% Clear zero:Automatic . Clear zero time:About 10s. Refresh frequency: 0.2-0.5S(120-1200RPM),0.25-0.06S(2400-9999RPM). Response frequency:100HZ. Measure indication:(RPM Less than 5000,2),(RPM 5000,3). Sign:NPN 5 wires normally open. Display: 4 red LED. Tachometer size:79 x 42 x 25mm. Panel cutout size:76 x 39mm. Hall proximity model:-5002C . Detected objects: Magnet. Detection range: 1mm-10mm. Proximity output current: 20mA(For the sensor). Operating temperature: -10 to 60C. Sensor wiring:brown(Power+),black(Test+),blue(signal). Sensor size: 60 x 10mm. Sensor wire length:1.2M Magnet:10x2mm Function selection: 1.Reset or manual reset on power. 2.Store the data (no power). Material: metal + plastic Package include: 2 x Red LED tachometer 2 x NPN hall proximity sensor 2 x magnet 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.