The ST Racing Concepts CNC Machined Aluminum Rear racing shock sets feature threaded aluminum shock bodies with O-ring installed pre-load collars in which the O-ring secures your pre-load adjustments in place. Threaded shock bodies allow for very precision ride height/spring pre-load adjustments, while the shocks also feature aluminum lower shock caps to keep the shock cartridge straight and flex free during suspension operation and heavy suspension compression. Compatible with: Slash 2wd, Slash 4x4, Stampede 4x4, Bandit, Rustler, Monster Jam vehicles (Use Grey Ultra Shock internals)