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 5081
 - BRIGGS & STRATTON 5081D
 - BRIGGS & STRATTON 5081K
 - BRIGGS & STRATTON 5081H