As with all iShock's the M1-A3 is completely tunable 100 percent rebuildable Adjustable nitrogen pressure Adjustable spring preload Adjustable rebound damping 12mm hard chrome plated chromoly shaft Aircraft grade 6061 aluminum body Japanese NOK brand seals Spherical bearings at mounting points Chrome silicone progressive rate spring Completely tunable and rebuildable 100 percent satisfaction guarantee Lifetime manufacturer�s warranty