After more than a decade of ruling the roads with the road proven 440 Series shocks, unveiled another breakthrough design. Dubbed Frequency Sensing Technology (FST) for its unique ability to dynamically adjust damping as you ride. The result is superior performance no matter the road conditions. A top mount threaded preload adjuster allows for fine tuning with a simple twist of the cap. Deflective disc valve. Adjust spring pre-load by hand, no special tool needed. Progressive rate spring. Standard spring rate and chrome finish.