The Quad Coupler 1.5 will clamp from 1.25” OD to 1.5” OD tubing, as well as 1" pipe (1.315" OD.) The Quad Coupler 1.5 is 1.25" thick. The Quad Coupler 1.5 will also bolt to 1-1/4" square tube locking the clamp parallel with the 1-1/4" square tubing using the notched side on the outside of clamp across the 1.26" flats. Or you can use the other outer face to bolt to a fixture, or allow the Quad Coupler 1.5 to rotate when fastened to a surface. The distance from the bottom of the clamped pipe or tube, to the flat or notched connecting surface, is .84" Complete with 3/8” x 1.25” socket head cap screw with nylon insert lock nut and Belleville spring washer.