Swivel top bracket provides vertical and tilting adjustment for trailer bunks. Swivel bracket for mounting bunk boards to bolster brackets. Bolt-on installation. 11 gauge material. Sold, individually. Model # 10201G40 Features: Bunk Flange holes 3/8 inch diameter Bunk Flange 1-3/8" x 3-1/2" Swivel Flange Hole 1/2 inch diameter Swivel Flange 2" tall x 3-1/2" 2 inch bunk Flange Hole centers Item Dimensions: 4" L x 4" W x 2" H.