With Shimano OT-SP41 Shift Outer Casing for Road / MTB the entire length of the outer casing is pre-lubricated with a special silicone grease for quick and precise shifting performance.
OT-SP41 maximally reduces the inner cable friction to provide quick response to operations and easy/effortless shifting. Moreover, power loss due to delay in shifting and fatigue by shifting especially when you ride on the terrain with many ups and downs as well as a long distance is also reduced.