RAM C Size Aluminium Square Rail Clamp 2.5" (RAM-247U-25)Included: 1 x RAM C Size Aluminium Square Rail Clamp 2. 5" (RAM 247U 25) The RAM 247U 25 is a clamp base with 1. 5" rubber ball that will connect to rails up to 2. 5" maximum in width. FEATURES Clamping base ideal for square posts up to 2. 5" in width Included C size 1" RAM rubber ball allows for connection to any C size RAM double socket arm; ball and socket technology allows for near infinite adjustability Made of powder coated, marine grade