Hall Measurement: This digital tachometer has good stability and high accuracy. Using a Hall sensor, Hall measurement is accurate, speed measurement is reliable, and the anti-interference ability is strong. LED Display: The digital tachometer comes with a 4-digit LED display, which makes the speedometer clear and easy to read. The backlight is standard for easy use at night or in dark places. Standard Size: Hall sensors are available in standard sizes for easy installation and transport. Suitable for various speed measurement applications. Input Pulse Signal: NPN/PNP open collector, contact switch, non-contact switch, level pulse. Input Signal Voltage: Low level: -30V~0.6V, High level: 4-30V. Measurement Range: Frequency: 9999H, 999.9H, 99.99KH, automatic switching. Measurement Accuracy: ±0.1%, reading ±1 digit. Display mode: Blue LED Four-digit reading 0-9999. Display refresh rate: > 3 times/second. Working Power Supply: DC8-24V, 30mA. A 5v power supply version is also available. Dimensions: 79×42×25mm. Installation size: 76×39mm. The Hall sensor is an NPN normally open type. The sensing distance of the Hall sensor is 10mm. The installation diameter of the Hall sensor is 12mm and the wire length is 1.2m. Please note: 1. Avoid strong electromagnetic interference; 2. The Hall switch and magnet must be firmly connected during testing, otherwise vibrations will occur, causing jumps or inaccurate readings, and the distance between the Hall switch and the magnet must be less than 10 mm. Note: The data are all manually measured, please allow 1-3 cm error. Due to differences in light and display, there may be some color differences, please refer to the actual item received.