Good stability, high precision and strong anti-interference ability. The exterior appearance adopts standard size and easy to install. Input pulse signal: NPN / PNP open collector, contact switch, non-contact switch, level pulse. Input signal voltage: low level: -30V -0.6 V, high level: 4-30V. Measuring range: frequency: 9999Hz, 999.9HZ, 99.99KHZ, automatic switching selection. Features: Measurement accuracy: 0.1% Display mode: 0.56 "LED Display refresh rate: 3 times / s Working power supply: DC8-24V, 30mA, measuring range: 10-9999 rpm Proximity switch: magnetic Appearance size: 80 x 42 x 25mm / 3.14 x 1.65 x 0.98 inch LED display (optional): red, blue Weight: 80g (red), 105g (blue) Overflow display: the first indicates "1" or "-1" and the last three do not show Precautions: / p 1. Connect the plug correctly according to the wiring diagram. 2. Should avoid strong electromagnetic interference and it is better to use shielded wire or double stranded wire to measure conductors 3. The counter count signal and the switch of the reset signal input or circuit should be as close as possible to the counter terminal to make the signal line as short as possible. 4. Avoid using cables like Note: this does not include other things, the color is based on the first picture, and the other pictures only show the effect p Due to the differences between different monitors, the picture may not reflect the actual color of the item. Due to manual measurement. Please allow deviation. Thank you!