Adjustability is one the most                                                   important things when tuning in                                                   your street car's suspension.                                                   That is why we have taken the                                                   time to develop the Ultimate "on car" adjustable upper control                                                   arms for the rear on your GM                                                   vehicle. There were no short                                                   cuts when manufacturing these                                                   arms, only the best materials                                                   and components money can buy                                                   were used to build our  "Ultimate Arms". Well known                                                   weak areas where other                                                   manufactures use mild steel have                                                   been replaced with aircraft                                                   quality 4140 chromoly steel                                                   featuring a TIG welded                                                   construction. The upper control                                                   arm mounting points feature CNC                                                   machined 0.250" mild steel, 4140                                                   Chrome-Moly tube adaptors and a                                                   high strength 4140 chromoly                                                   heat treated 1.000" solid                                                   adjuster; truly overkill for                                                   any application!