SEARON Digital Inductive Engine Hour Meter and AC/DC Hour Meter of 5-277 Volt for Generator Motocross Tractor Cultivator ATV Trailer Sprayer Compressor Robot Milking Trimming Digital Inductive Hour Meter and AC/DC Hour Meter of AC/DC 5-277 Volt for Truck ATV Lawn Mower Chainsaw Compressor Tiller Chipper Marine Farm Tractor Excavator Has 2 trigger ways: Triggered by the spark of engine or Triggered by any AC/DC 5-277 volt power. Accumulating total running time. Non-re-settable total time reads up to 99,999 hours with 0.1 hour resolution. Record 2 re-settable JOB time: TMR1 & TMR2. JOB time reads up to 99,999 hours. Internal CR2050 battery, Total hours remains visible when engine/power is off. 2 Years Warranty