The Shimano polymer shifter cable set OT-SP41 for MTB contains shifter cables with a polymer coating. Viewed under a microscope, it is reminiscent of tubes wound around the cable. This reduces the surface rubbing against the liner and contributes to better grease retention. It results in reduced shifting forces and noticeably faster shifts.
The set also includes the SP41 cable housing, which has been pre-lubricated over its entire length with special grease. This grease is low-friction and very durable.