Install Operation: Wrap the end of the induction wire around the spark plug tube 5 times, then secure it with a cable tie. Insert one end of the induction wire into the groove on the back and mount the unit in a suitable location using screws. Inductive Digital Hour Meter with Waterproof LCD Display for Motorcycle, ATV, Snowmobile, Marine Boat, Jet Ski, and Gas Engine – not a tachometer model Features: New and high quality Tracks vehicle service life for oil changes, valve adjustments, spark plugs, and other maintenance Easy to install Peel-and-stick mounting base No battery required – powered through induction from spark plug wire Compatible with most gas engines Records and displays up to 9,999.9 hours Hourglass symbol flashes during operation to indicate active timing Automatic rollover after 9,999.9 hours Time resolution: 0.1 hour Fully encapsulated in 100% epoxy for protection against water, shock, and temperatures up to 85°C Specification: Item size: 54 x 36.5 x 14.5mm Packing content: 1 x Hour meter 1 x Induction wire 2 x Mounting screws