Usage Tips:This digital Tach/Hour Meter will keep track of engine RPMs and running time for all types of gasoline powered engines. The unit is powered by an internal lithium battery(CR2430) so no external power connections are required. The operation of the Tach/Hour Meter is connected by 5ft. insulated wire. You will wrap the RPM wire around the spark plug. The Tach/Hour Meter is activated by the spark of the engine. Because the unit is activated by the spark of the engine it will keep track of the actual hours/duration of operation. This Tach/Hour meter is useful for maintenance or warranty applications for any type of gasoline powered engine. Features: Multiple Functions: including functions of total timing, single timing, maintenance reminder, rotate speed, engine stroke selection, maximum speed checking, etc. Maintenance reminder function: the maintenance time can be set manually according to the maintenance requirements of the engine. The maintenance time is displayed in countdown. Two groups of maintenance time can be set, with the setting range of 5-50H and 10-250H respectively. Total Timing & Single Timing Function: total timing can record the total running time of the engine, and the total timing cannot be reset. And the Single timing can record the time of single operation of the engine, which can be reset by pressing the key. Rotate Speed Function: after continuously detecting the engine ignition signal, the main interface displays the current engine speed. Rotate speed range is 0-30000rpm. You can view the maximum speed when the engine is working and reset it. Easy to Install: just fix it with screws or double-sided paste. No Power Connection Required: powered-up by the built-in CR2430 button battery, and the normal service life is 5 years. When the engine stops working, the total operating hours of the engine can be displayed normally. Good Waterproof Effect: the waterproof grade up to IP67. Suitable for gasoline engines with different ignition modes, 7 engine strokes can be selected(1P1R, 1P2R, 2P1R, 3P1R, 4P1R, 6P1R, 8P1R, the default is 1P1R). Common Applications: 2/4 Stroke Engines, RC Toys, PWC, ATV, Motorcycles, Marine Engines, Chain Saws, Tractors, Lawnmowers, and gas powered tools. Specifications: Color: Black Display: LCD digital Timing Range: 0-9999H Single Timing: 0-99999H Maintenance Range: 5-10H 10-250H Timing Accuracy: 1MIN/0.1H/1H Rotate Speed Range: 0-30000RPM Rotate Speed Accuracy: 10RPM Refresh Rate: 0.5s Power Supply: Internal Battery(CR2430) Water-proof/Dust-proof Grade: IP67 Induction Line Length: 1.75m / 5.74ft Display Size: 36.4 * 14.4mm / 1.43 * 0.57in Item Size: 76 * 40 * 20mm / 2.99 * 1.57 * 0.79in Item Weight: 65g / 2.31oz Package Weight: 82g / 2.89oz Package Size: 19 * 11.3 * 2.5cm / 7.48 * 4.45 * 0.98in Packing List: 1 * Digital Tachometer