3 inch tube diameter only;Made from 10 gauge thick steel;Bare steel; California Residents: WARNING This heavy duty truss system is designed to take serious abuse and reinforce your entire axle especially at higher speeds. The one-piece 10 gauge thick truss offers a unique shape that offers maximum rigidity. This is a universal truss for fabricated and stamped axle housing. Simply trim out the shape of the center section and fit on. Since there are so many different 9 inch housings on the market now and since many of them can be slightly offset or centered, this universal truss allows you fit nearly any housing. For prevention of warping it is recommended to not weld with too much heat, let your weld cool and move to another part of the truss to weld, and take your time. This will help to keep your axle true. NOTE: This truss has no cutout for the center section. It will require trimming to fit. This kit requires general welding and fabrication skills.