1. LCD display, low voltage design, built-in battery (CR2450) power supply mode, inductive design, safe and reliable. 2. A of measurement methods: After one end of the electronic wire is installed on the electronic watch casing, use a metal clip to clamp it on the spark plug wire sheath for inductive measurement; the electronic wire is bundled on the spark plug wire sheath and wound for a few times to sense and measure; handheld The tachometer measures 3 cm to 5 cm near the sheath of the spark plug wire. 3. (1) Timing range: 1 minute to 99999 (min MIN). (2) Speed mode setting: long press (SET) key, the screen will display 01, 02, 03, 04 in sequence; (screen 01, 02, 03, display the speed mode corresponding to various engine strokes) The factory default value is 02 Speed mode. Releasing the button with your finger will flash the displayed data for 3 to 5 seconds and then confirm the start of the speed mode, and then you can measure. (3) Shut down: Hold down the (SET) key, the screen will display 01, 02, 03, 04 in sequence; when the screen displays 04, it will flash for 3 to 5 seconds. After stopping, confirm to start the system reset mode, and press the (MODE) key at the same time Press and (SET) until the full screen is displayed (the recorded working time and speed data are cleared). (4) Long press (MODE) key to view historical high speed data. (5) The above multi-model products are applicable to all: gasoline (engines, chainsaws, lawn mowers, gliders, motorcycles, automobiles, karts, engineering vehicles, snowmobiles, ATVs, motor boats, grinders, generators, Vibration machine) mechanical equipment and so on Type: Digital Tachometer Measuring range: 100-20000 Measurement accuracy: 1% Resolution: 100% Power supply: button battery Colour:As Shown Material:plastic Package Contents: 1 x Tachometer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.