The RAM-235U Medium Dual Stainless Steel U-Bolt Pipe Mounting Base is designed to fit a 1 inch to 1.25 inch diameter round pipe. The base is constructed of Marine Grade Aluminum with a Black Powder Coating and has a 1.5 inch diameter Rubber Ball. For extra holding power, the base connects to a pipe with two stainless steel 1.25 inch u-bolts.