Due to popular demand, we now carry 8mm coils to provide a stiffer option than the 7mm coil that comes with our shocks by default. This listing now includes both 7mm and 8mm Coils to try for only $30 extra! ($120 added coil value). Initially developed for our ATV shock conversion kits made in 2004, we set out to develop the best adjustable shock under $250. 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. Compatible with our 90cc Shock Conversion Kits and Rear Shock Conversion Kit (Same size as stock 300ex shocks) 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.