YueYueZou&reg; Waterproof Tach Hour Meter Tachometer for 4 Stroke Gas Engine Motorcycle ATV Snowmobile Boat Inductive Hour Meter for Marine,ATV,Motorcycle,Dirt,Ski Track the Service Life of Your Vehicle-Oil Changes,Valve,Adjustments,Spark Plugs,ect Works on Any Gasoline Engine. No Battery Required - connects to spark plug wire. Easy Installation-peel&stick,no wiring necessary,or attach with enclosed hardware. No Battery Required-connecys to spark plug wire. Works on Any Gas Engine. Records and Displays to 9,999.9 Hours.Stand-by Time up to over 20,000 hours. Hour Glass Symbol Appears and Flashes on/off to Indicate Counting Time