Features:  Mini size, high performance and fast reaction speed.  0.56" LED 4-digits display, clear and easy for readings.  Rotate speed measuring range: 5-9999RPM; frequency range: 0-98990.1Hz.  Setting parameters will be memorized when power off.   Suitable for detecting the speed of every kind of motors.    Tachometer Rate Setting Instructions:  1. Rate range: 1-99(default 01: display value is same with actual value; if the rate is 10, display value*10=actual value);  2. When power on, the meter display "0";  3. Press "SET" button, display "1"; press again, display "01"...  4. When display "1", is measuring RPM; press "ADD", from "1" to "2", when display "2", is measuring frequency; display "01" is for rate setting, short press "ADD" for +1, long press for +10;  5. After setting the values, it will be stored if no operation in 10s, return the selected function interface;  6. With 1 decimal point, that is when rotate speed is <1000RPM, the rotate speed corrects to 1st digit after the decimal point; no decimal point when >1000RPM.  Tips:  User can set the appropriate rate so as to measure frequency, less than 100KHz (999.9*99=98990.1Hz).    Specifications:  Display: 0.56" 4-digit LED  Display Color: Blue / Green / Red (Optional)  Rotate 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. 2RPM; >5000RPM: Approx. 3RPM  Input Signal: Voltage Pulse Signal, Active Contact Signal, PNP, NPN  Power Supply: DC 8-15V  Installation: Embedded  *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 rotate speed separately.    Package List:  1 * Digital Tachometer