Rotary Corp brand aftermarket product. Tach/Hour Meter. Records actual running of engine. Non-Erasable. Shows Engines RPMs (Read up to 9,000 RPMs). Alerts you to lube (Grease) & Change Oil (25 Hour Intervals). No battery required, Triggered from the Spark Plug Wire.Replaces:Fits BRIGGS & STRATTON 5081BRIGGS & STRATTON 5081DBRIGGS & STRATTON 5081KBRIGGS & STRATTON 5081H