Nitro 9000 series shock absorbers incorporate self adjusting "Velocity Sensitive Valving". This revolutionary technology varies the resistance valving incorporated in the shock according to piston rod speed. This allows for a super smooth highway ride and outstanding control in rugged off road situations from the same shock, without turning any knobs or shock removal for re-adjustment. Performance Proven 10-Stage Variable Valving 200 psi Nitrogen Charged Massive 1 3/8" Bore Chromed Hardened 9/16" Piston Rod Spring Loaded Piston Rod Seal Military Spec. Fluid Rated To –50° C • Poly-urethane bushings for long life Limited Lifetime Warranty Smooth Highway Ride/Firm Off- Road