It can accurately test the RPM value of engines. Features: Mini size, high performance and fast reaction speed. 0.56 4-digit LED display, clear and easy for readings. Mini taille, haute performance et vitesse de raction rapide. cran LED 0,56 4 chiffres, clair et facile pour les lectures. Rotational speed measuring range: 5-9999RPM; Frequency range: 0-98990.1Hz. The setting parameters will be memorized when power off. Suitable for detecting the speed of all kinds of motors. Tachometer rate setting instructions: 1. Rate range: 1-99 (default 01: the display value is the same as the actual value; if the rate is 10, the display value * 10 = actual value); 2. When power on, the meter displays ??0???; 3. Press SET button, display 1; press again, display 01... 4. When display 1, measure RPM; press ADD, from 1 to 2, when display 2, measure frequency; display ??01?? is for rate setting, short press ??ADD?? for +1, long press +10?; 5. After setting the values, it will be stored if no operation in 10s, return to the selected function interface; 6. With 1 decimal point, that is, when the rotation speed is 1000RPM. Tips: User can set the appropriate rate in order to measure the frequency, less than 100KHz (999.9*99=98990.1Hz). Features: Display: 0.56 4-digit LED Display Color: Blue/Green/Red (optional) Rotation Speed Range: 5-9999RPM Frequency Range: 0-98990.1Hz Rate Setting Range: 1-99 (Default: 01) Reset Time: 10s Refresh Time: 120-1200RPM: 0.2~0.5s; 2400-9999RPM: 0.25~0.6s Accuracy: 5000RPM: Approx. 3RPM Input Signal: Voltage pulse signal, active contact signal, PNP, NPN Power Supply: DC 8-15V Installation: Built-in *Wiring: +12V: DC 8-15V Input Positive GDN: DC Power Negative IN+: Signal Input Panel Dimension: 72*36*20mm/2.83*1.42*0.8in Item Weight: 25g/0.88oz Note: The sensor is not included, this tachometer can not be used to test the car rotation speed separately. Package List: 1 * Digital Tachometer