The SuperPro Front Arms are a standard replacement with Bushings and Ball Joint. Front Caster/Radius Arms utilize a SuperPro Bushing with a heavy duty Ball Joint. The Bushings allow full articulation and movement without binding and with no increase in noise, vibration or harshness. SuperPro Tip Designed and packaged to be replaced as a pair. SuperPro maintains it is critical for a pair to installed to any application at the same time to avoid any detrimental handling and braking characteristics from a mismatch of bushing material.