Searon Digital Hour meter Tachometer 2 & 4 Stroke Small Engine Spark For Boat Outboard Waterproof Black Resettable Digital hour meter tachometer motorycle, snowmobile, jet ski, motocross, ATV,boat, generator,lawn mowers,boat Works on any 1P1R(1 Plug 1 revolution),2P1R & 1P2R gasoline engine Read up to 99,999.9 hours/30,600 rpms Speed/filter display update can be set to 1s or 0.5s. Resettable sensitivity of high / low