All iShock's feature externally adjustable rebound damping with adjustable spring pre-load. The iShock F-8 reservoir model also includes adjustable compression damping. For durability, HDUSA uses nothing but the best materials, treatments and coatings technology has to offer including 16mm hard chrome plated shafts and aircraft quality billet aluminum throughout. As with all iShocks, the F-8's are totally rebuildable and completely tunable to every possible riding scenario. Backed by a 100% satisfaction guarantee and a lifetime warranty, the iShock is the right choice for amateurs and pros alike.