Initially developed for our ATV shock conversion kits made in 2004, we set out to develop the best adjustable shock under $1,000. After years of feedback and improvements, we are happy to provide a shock that can be used on ATVs, Motorcycles, and other off-road vehicles to upgrade stock suspension performance. These shocks are adjustable in length, spring preload, and rebound: Length can be adjusted by unscrewing the lower shock eye, and threading nut to desired length. Preload can be adjusted using included tool to tighten the nut/collar above spring coils. Rebound can be adjusted by twisting the knob near the lower shock eye 0-24 clicks.