Clamp - Riser - OG - Black For customers who have already purchased OG handlebar risers from Thrashin Supply, Updated top clamp features 1/4-20 drilled and tapped holes on its underside, Hardware not included, Made in U.S.A., Not required for newer Thrashin Supply risers with top clamps that are already drilled with the 1/4-20 holes on the underside.