Electronic Specialties 329 Black 2.5"x 1.3" x 1.5" Small Engine Tachometer/Hour Meter RPM in real time - Stable RPM readings on small engines. You choose the display update rate - twice per second or once per second. RPM Range: 0-20,000 RPM MAX RPM - Viewable and resettable, you can record the engine's MAX RPM over time. MAX RPM can be viewed or reset at any time after engine is shut down HOUR METER AND ENGINE/JOB TIMER TOTAL: This function records the accumulated total engine hours, up to 99,999 hours, in three different modes. This can be set for service intervals up to 200 hours Specs - RPM: 0-20,000 RPM - Refresh rate: 0.5S or 1S - Hours: 0-99,999 hours - JOB hours: 0-99,999 hours - SVC hours: 0-200 hours - Hour meter resolution: .1H or 6 minutes - Battery: CR2032 coin type (replaceable)