Searon LCD Digital RPM Tachometer Hour Meter Waterproof for ATV Chain Saw Compressor Lawn Mower Marine Tractor Excavator Digital Inductive Tachometer and Hour Meter for for ATV Chain Saw Compressor Lawn Mower Marine Tractor Excavator Hours display from 0-99,999.9 hours with 0.1 hour resolution. when total hours run up to 9999.9 hours, the resolution is 1 hour Accumulating engine total running hours (TOT). total hours are non-resettable.Record 2 groups of Partial hours: (TMR1 & TMR2). Partial hours are resettable.Customizable warnings and maintenance reminders from 1-1000 hours with flashes alert service alarms. The default Maintenance reiminder intervals are 0 hour Tachometer read up to 20,000 RPMs with 10 RPMs resolution.Max RPMs can be recalled and viewed Meter will work through internal battery or External power of DC 5-65 Volt. If the internal CR2032 battery run out, meter will still work through external DC 5-65 Volt power.