I cut and pasted this from Cabela's website - is this the one you've got
DTG? I see I was wrong, it is 2 1/4" diameter. It's something like $90


"Mount and position sonar and GPS units for optimal performance.
Heavy Duty RAMŽ Mount - Made of powder-coated marine-grade aluminum with a larger plate to support all big-screen, 8-10" sonar/GPS units, including Lowrance, Garmin and Raymarine. Has a 3-1/2" arm with a D size 2-1/4" rubber ball. 11"W plate. "