After more than a decade of ruling the roads with their road proven 440 Series shocks, Progressive Suspension 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.
Frequency Sensing Technology (FST)
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
Progressive rate spring
Standard or heavy duty spring rate and black or chrome finish
Lifetime Limited Warranty & made in USA
Note: Heavy-duty shock applications are recommended for bikes with additional add-on accessories, rider weight over 250 lbs. or passenger use over 50% of the time. Sold in pairs.