The LATNEX HM-028 Multifunction Digital Hour Meter measures the working time and real-time RPA value of gas engines (detected by the spark plug). It has a multi-colored backlight, RPM reminder, maintenance or volt status, and a waterproof design that makes it perfect to use in all weather conditions. Product features: Tachometer: RPM / Max RPM / Alert RPM Hour Meter: Total hours Resettable JOB timer Maintenance service timer: SVC&SVC1 Clock Volt: Volt / Max RPM / Alert Volt Backlight color change Replaceable internal battery Waterproof IP65 Specifications: Product size: 79x41x21.4mm Screen size: 51.3x23.3mm Battery type: CR2450, 540 mAh Waterproof rate: IP65 Display mode: LCD Application: Paramotors, Microlights, Marine Engines - Inboards and Outboard Pumps, Generators, Mower, Model Boats, Motor Cycles, Scooters, Cleaners and Chainsaws etc. User Manual