Uses 2 Soft standard rubbers on the insides and the 2 Mauve poly on the outside.
HARD OUTERS / SOFT INNERS - STOPS BRAKE WEAVING.
Don't be confused as this special shore hardness set up was proven after 2 years of testing and is perfect for race and road, having now been sold for over 10 years with success.
If you require a harder black rubber bush use
C-STR628.