18-24 Softail, (except 18-20 FXFB, 18, 20 FXFBS 114, 18-24 FLSB, 19-20 FXDRS 114, 19 FXFB 114, 20-24 FXLRS, 21-24 FXFBS, 22-24 FXLRST, 22 FXRST)
Progressive Suspension has combined their road smoothing Frequency Sensing Technology (FST) damper with a progressive rate spring to create a state of the art fork cartridge kit.
What is F.S.T.?
Our proprietary patented technology that has the unique ability to dynamically adjust damping as you ride. What this means is whether you`re hitting the small or big bumps in the road, the Monotube distributes oil through ports accordingly to soak up the hit making for an ultimately comfortable ride.