Koso Proton RPM / Hour Meter Monitor your engine's performance accurately with the Koso Proton RPM & Hour Gauge. This device not only tracks the engine's RPMs but also tallies the total operating hours, ensuring you have precise data on your engine's workload and operating time. Ideal for maintaining peak performance and tracking routine maintenance schedules. Features: Digital tachometer 0-20K RPM Max RPM Total engine hours Resettable engine hours