Auto Meter 3209 Tachometer Shock Mounting Adapter It is a mounting strap Direct replacement for any 5 inch pedestal mount Tach with a inch step-down inch case (ie 3 3/8 inch diameter section where the strap mounts) Includes base assembly kit Can also be used to convert most 3 3/4 and 5 tachometers to pedestal mount Use with your quality instruments for maximum performance