Parts 444-4020B Black 13" Heavy Duty Big Mile Riders Rear Suspension Shock

Frequency Sensing Technology (FST), allows the shocks to sense the frequency of a bump and automatically adjust damping for superior ride quality
Deflective disc valve
Adjust spring pre-load by hand, no special tool needed
Progressive rate spring
Heavy duty spring rate and chrome finish

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.