1/2", Malleable Iron Beam Clamp, -13 Threaded Openings, Fits Flanges Up To 1" Thick, Supports Threaded Rod, Threaded Brindle Rings & Electrical Boxes, Malleable Iron With Electroplated Bright Zinc Plating, Set Screw Rating 1,250, Static Load Limit 1,300 LB, Based On A Safety Factor Of 3, Load Rating Based On Bottom Hole Of Beam Clamp, Torque INLB 250.