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 the right position and fix the watch with screws. Features: 1.Brand new and high quality 2. Track vehicle life - oil changes, valves, adjustments, spark plugs etc. 3. Easy installation and stickNo battery needed - connect to spark plug wire. 4. Works on any gas EngineRecord and displays up to 9,999.9 hours. 5. The hourglass symbol appears and flashes on/off to indicate the countdown time. 6. Automatic conversion. 7. Resolution: 0.1 hour 8.100% epoxy resin housing is waterproof, shockproof, fireproof at 85 deg condition; C Specification: Size: 54*35*14mm Net Weight: 52g Packing Contents: 1 x Hour Meter 1 x Cable 2 x Screw