These polyurethane bushings are a direct replacement for the soft rubber bushings in the spring seat, also known as a spring perch or spring saddle. Rubber bushings offer a more compliant ride, but oxidize and deteriorate over time and even when new compromise handling by introducing a significant deflection in the suspension. Polyurethane bushings by contrast do not degrade in the same manner and largely remove the deflection of rubber. Sold as a set of four. One set does both front spring perches.