ACDelco 519-21 Specialty Rear Spring Assisted Shock Absorber Constant rate front coil springs can help improve stability and maintain ride height Variable rate rear coil springs provide 500 lbs (per pair) of load capacity. [Not to exceed vehicle GVWR (Gross Vehicle Weight Rating). Product does not increase payload.] Seamless Drawn-Over-Mandrel (DOM) tubing decreases internal component wear, resulting in longer service life Super finished, chromed, piston rod provides anti-corrosion properties, a more consistent wear surface, proper seal lubrication, and longer product life Real-world tested to ensure that the shocks will fit intended vehicles and applications