UMI's  boxed lower control arms utilize our Roto-Joint technology for a bind free performance  and quiet comfortable ride quality. The boxed control arms are fabricated from  0.120" wall thickness rectangular tubing, CNC machined drawn over mandrel bushing  holders and MIG welded end caps to keep out unwanted road debris. Each control  arm features the correct provisions for adding a stock or aftermarket rear sway  bar, sway bar holes are reinforced with a 0.120" wall thickness steel sleeve that  is TIG welded and sanded into place. The solid construction combined with the  delrin lined Roto-Joints eliminate control arm flex and bushing deflection for  improved traction and reduced wheel hop. The Roto-Joint design is a pivot ball  lined with a greaseable delrin race designed to offer 28 degrees of total  unrestricted movement, more than adequate for a bind free, low friction  operation. The Roto-Joint design improves performance over the factory rubber  and aftermarket polyurethane bushings by allowing the suspension to articulate  correctly, and provide precision handling. The installed UMI Roto-Joint allows  rear end free movement when high handling, auto cross or road race is a concern  while still being a 100% streetable setup. The installed delrin race, which lines  the spherical ball, absorbs shock and road noise for a quiet and smooth  operation on any street or track driven vehicle. This control arm set features  Roto-Joints on both sides of the control arms. This is designed for maximum  performance and suspension travel. Roto-Joints are greaseable and low  maintenance making an excellent street setup for your cruiser or race car!