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 qualityTrack the service life of vehicle-oil changs, valve, adjustments, for spark plugs, etc.Easy to installPeel and stickNo battery needed - connect to for spark plug wireWorks on Any Gas EngineRecord and display to 9,999.9 hoursHour glass symbol appears and flashes on/off to indicate counting timeAutomatic roll overResolution: 0.1 hour100% epoxy encapsulated casing resists water, shock, stand fire of 85C Specification: Item size: 54*36.5*14.5mm Packing content: 1 x Hour meter1 x Wire2 x Screw About Our Company We are a professional car accessories supplier.