Keep track of important maintenance times for your Mammoth-oil changes, valve adjustments, spark plugs, etc. Usable with any gas engine. Records and displays up to 9,999.9 hours. Just peel and stick or attach with enclosed hardware. Connects to spark plug wire so no batteries are needed. Hourglass symbol appears and flashes on/off to indicate counting time. Resolution 0.1 hour. Hours automatically roll over. Safely and completely encased in 100% epoxy.