Patriot Docks Heavy Duty Pipe HolderThe HD pipe holder is fastened to the aluminum dock frame with two 1/2" bolt/nut fasteners. The zinc oxide-coated steel bracket clamps to 1 1/2" sch 40 Pipe with two 1/2" bolts to support the dock frame. The inside diameter measures 2-1/16"". ; The post sleeve is 12"" long with frame connection bolts that are 8"" apart.2-1/16"" i.d.; Patriot Dock components are modular to make it easy to customize the size and configuration for maximum versatility. We have prepared many dock packages which can be combined to almost any layout. You can add more sections or combine packages to make just about any configuration. Patriot Docks are the price leaders in the industry- big volume translates to low costs.