Standing four inches in height, the Johnson Outdoors Aluminum Fixed Base Downrigger Pedestal works with either surface or track mounting. The top plate is pre-drilled and tapped to allow the mounting of a Cannon swivel base and downrigger, as well as other swivel base and downrigger brands. Tapped to allow mounting of swivel base/downrigger Compatible w/ other swivel base & downriggers | Johnson Outdoors Aluminum Fixed Base Downrigger Pedestal, 4"