Rancho RS5039 RS5000 Series Shock Ten-stage velocity sensitive valving - Provides tuning specific for each vehicle 5/8-in. (16mm) diameter piston rod (select applications) - Adds strength and durability 1 3/8-in. (35mm) diameter piston (select applications) - Ensures performance in any environment Protective boot included - Protects the shock rod and oil seal Limited Lifetime Warranty - Guarantees your investment