- Keep track of engine operating times, oil changes, servicing, and fuel consumption. *Attaches easily with threaded mounting nut. *Connects to the ignition lock. * Works with any engine (e.g. cars, tractors, motorcycles, ATVs, etc.). *12/24 V. *Stores and displays up to 9999 hours 59 minutes. *Installation diameter: Ø 52 mm. *Outer diameter: Ø 57 mm. *Installation depth: 35 mm.