Hinge measures 5" in length including weld on mounting plates. Barrel measures 1" in diameter plus 5/16" mounting plates. Hinge pin is 5/8" diameter x 1-1/16" long & extends into the upper barrel. 1-5/8" spacing from post to gate frame for 90 degree swing. Hinge pin sits on ball bearing for easy pivot. Zerk fitting at top for lubrication with grease gun.