This Compact And Easy To Install Module Will Allow You To Easily Adapt Autometer Tachometers And Shift Lights And Many Other Aftermarket Rpm-Based Devices On Your Alternator-Equipped Diesel Or Non-Standard Ignition Gasoline Engine. Equipped With A Sensor Which Is Mounted To The Alternator Casing, A One Time Setup Calibration Is Accomplished Via Push Button Interface On The Module To Synchronize The Alternator Signal With Engine Crank Rpm. Perfect For Diesel Performance Applications Looking To Add A Tachometer Or Upgrade From Factory Equipment And A Great Problem Solver For Engine Swap Builds In Need Of Working Instruments. Pair It With Autometers Low-Rev Tachometer Models To Complete Your Diesel-Specific Gauge Installation.