These leaf spring axle perches are CNC laser cut and formed to fit 3" OD or 3.5" OD axle tubing. We also have a version specific for 2007-2021 Toyota Tundra's since the leaf springs are angled on the axle housing. They are 2.5" wide and 6" long for reduced axle wrap. The centering pin hole is 9/16", but depending on your leaf springs you may need to drill it slightly larger. These are a perfect compliment to our Camburg rear end housing or for spring-under conversions. These are much stronger and higher quality than the cheaper stamped versions you see out there. Sold in pairs.