RAM 6.25â X 2â Rectangle Base with 1â BallRAM 2.5â Round Base (AMPs Hole Pattern), 1â Ball & Mounting Hardware for Garmin Fishfinders & GPSMAP Devices. This mount has a three hole pattern which will connect to the base of the Garmin Marine GPS unit swivel mounts. Included is a hardware pack for assembly for your Garmin Fish finder.