Check the listing for details. 4 Digital Red LED Tachometer RPM Speed Meter+Hall Proximity Switch Sensor NPN. Condition: New. Listed at 13.80 USD. Descriptions： Power requirement: DC 8-15V Measure range : 5-9999RPM. Clear zero: Automatic. Clear zero time: about 10s.the greater the RPM value,the longer the clear zero time. Refresh frequency: 0.2-0.5S while 120-1200RPM;0.25-0.06S while 2400-9999RPM. Measure indication:RPM5000,±3. Display:RED 0.56” LED Sign:Pusle signal,Hall NPN 3 wires normally open. Hall proximity model:NJK-5002C Appearance:M12mm cylinder. Detection range: 10mm Proximity output current: 200mA Detected objects: magnet Response frequency: 100HZ Tachometer dimension:72x36x20mm,panel cutout Dimension:68x33mm. Sensor dimention: M12x10x55mm. Sensor wiring:brown-Power+;blue-Power-;black-signal. Operating temperature: 0 to 50°C. Packaging include： 1x Tachometer 1x Hall NPN proximity sensor Descriptions： Power requirement: DC 8-15V Measure range : 5-9999RPM. Clear zero: Automatic. Clear zero time: about 10s.the greater the RPM value,the longer the clear zero time. Refresh frequency: 0.2-0.5S while 120-1200RPM;0.25-0.06S while 2400-9999RPM. Measure indication:RPM5000,3. Display:RED 0.56 LED Sign:Pusle signal,Hall NPN 3 wires normally open. Hall proximity model:NJK-5002C Appearance:M12mm cylinder. Detection range: 10mm Proximity output current: 200mA Detected objects: magnet Response frequency: 100HZ Tachometer dimension:72x36x20mm,panel cutout Dimension:68x33mm. Sensor dimention: M12x10x55mm. Sensor wiring:brown-Power+;blue-Power-;black-signal. Operating temperature: 0 to 50C. Packaging include： 1x Tachometer 1x Hall NPN proximity sensor