This item is a digital tachometer gauge and hall proximity set. Both of the tools are made of quality plastic for wear resistance purpose. The tachometer measuring range is 9999 and it will show "1" or "-1" when the data is its measuring range. Feature - This meter works with many kinds of devices - With digital , nice actual rather than relying on guesstimates. - The hall sensor will light up to let you is getting power. - It shows the measuring data accurately, and they are easy to install. - The meter is designed to snap into a rectangular opening for flush mount. Specification - Color: Mainly Black - Material: Plastic - Tachometer Size: 79x41x25cn/31x16x9.8inch - Hall Proximity Size: 40x22x12mm/1.6x0.9x0.5inch - Power requirement: -24V 30mA - Measure range : 10-9999 . - Refresh frequency: 0.2-0.5S@120-1200 ;0.25-0.06S@2400-9999 . - Measure accuracy: <5000,±2; >5000,±3. - Hall proximity model: CF5135C-Z - range: 10mm - Detected objects: Magnet - Response frequency: 9999Hz,999.9hz,99.99khz - Sensor wiring:brown means ; blue means power-; black means . - Operating temperature: 0 to 50°C. Package list: 1 x Tachometer 1 x Hall Proximity Sensor