Excuse the crude cut and paste. This is from the SPC Website: "FSR" or "Future Shock Rear" was the original name that Specialized assigned to our patented 4-bar linkage design. In the early and mid-90's, Specialized manufactured a front shock named "Future Shock". "Future Shock Rear" seemed to be a logical extension of that name for rear suspension. Every FSR rear suspension utilizes a Specialized Patented design, which some refer to as the "Horst Link", and differs from other "4-bar link" rear suspension because of their efficient suspension action and pedaling, and independent braking forces that do not affect the suspension motion.