This tachometer with small size, high performance and fast response speed is great for detecting the speed of all kinds of engines. It can test the speed value of engines accurately. Features: Mini size, high performance and fast response speed. 0.56'' 4-digit LED display, clear and easy to read. Speed measuring range: 5-9999 RPM; Frequency range: 0-98990.1Hz. The setting parameters are saved when power off. Suitable for detecting the speed of all types of motors. < strong>Tachometer rate setting instructions: 1. Rate range: 1-99 (default 01: the display value is the same as the actual value; when the rate east of 10, the display value * 10 = actual value); 2. When power on, the meter displays "0"; 3. Press the "SET" key, display "1"; press again, display "01"... 4. When "1" is displayed, measure the speed; press "ADD", from "1"; when "2", display "2" measures the frequency; display "01" is for rate setting. Short press "ADD" for +1, long press +10. 6. With 1 decimal point, that is,