Install Operation: Wrap the end of the induction wire around the spark plug tube 5 times, then fix it with a cable tie, then insert one end of the induction wire into the groove on the back, find a suitable position and fix the watch with screws. Inductive Digital Hour Meter Waterproof LCD Display for Motorcycle ATV Snowmobile Marine Boat Ski Gas Engine, not tachometer model Features: Brand new and high quality Track the service life of vehicle-oil changes, valve, adjustments, for spark plugs, etc. Easy to install Peel and stick No battery needed - connect to for spark plug wire Works on Any Gas Engine Record and display to 9,999.9 hours Hourglass symbol appears and flashes on or off to indicate counting time Automatic rollover Resolution: 0.1 hour 100 percent epoxy encapsulated casing resists water, shock, stand the fire of 85¡ãC Specification: Item size: 54x36.5x14.5mm Packing content: 1 x Hour meter 1 x Wire 2 x Screw