Features the all new Frequency Sensing Technology (FST) which allows the shocks to sense the frequency of a bump and automatically adjust damping for superior ride quality. Deflective disc valving. Adjust spring pre-load by hand, no special tool needed. Includes a progressive rate spring and is high-pressure gas charged for consistent performance. A shock which is slightly longer than stock may alter the head angle slightly and provide somewhat quicker steering.. A shock which is slightly shorter than stock may slightly alter the head angle and provide somewhat slower steering.. Heavy Duty Applications are recommended for bikes that are operated at or near the manufacturer’s maximum load rating over 50% of the time.. Before purchasing or attempting to install shocks that are different than the OEM length, confirm that your wheel travel can be altered without causing clearance issues such as swingarm/axle to exhaust contact as well as chain/belt guard or tire contact..