Galvanized Heavy Duty Swivel Brackets.3/16" galv steel, 3-1/2"wide,2"high with a 1"long lip.Use with Extra heavy adjustable bunk brackets for proper angle of bunk or bolster boards to the angle of the boats hull.Swivel bracket bolt hole is 1/2"DIA.The two bunk attaching holes accept 3/8"DIA lag or thru bolts..Made in U.S.A. Sold as each