Handcrafted 6061-T6 aluminum extended swingarm. Proprietary custom extrusion made exclusively for Brock's Performance. Extends wheelbase from stock to 3 inches over. 3-position shock mounts allow flexibility in ride height (stock, -1”, -2”). Designed for use in high-power, high-torque applications. Includes centerless ground 4130 Chromoly axle (choose from 3/4”, 25mm, 1”, or 28mm axles). Reversible billet aluminum axle adjusters for easy wheel adjustments. Select from one of two caliper mounting options: Undermount - For Aftermarket Calipers. OEM - For using the OEM Dyna Caliper and Mount (select the correct axle size for your caliper mount). PTFE® lined spherical bearings from Worldwide Bearings preinstalled. Select bushing size for the model year Dyna: 11/16” - Model Years 2000-2005. 3/4” - Model Years 2006-2017. Interior swingarm width measures 10 5/8” at the axle. The total weight of swingarm, hardware, and axle is 14.78 lb. (6.70 kg). Designed, machined, and assembled in the USA. Burnished raw aluminum finish.IF YOU WOULD LIKE A DIFFERENT AXLE OR PIVOT SHAFT OPTION PLEASE LET US KNOW WHEN PLACING YOUR ORDER.