The Invader SS are Trailmaster's lowest priced performance shock absorbers. HeavyDuty twin-tube construction protects the inner shock from damage.A tough white enamel finish withstands rust and corrosion. These shocks have multi-stage compression valving, and large, sintered-iron 35mm piston heads. Also included are the urethane bushings for increased shock performance, the dust boots are sold separately.