Replacement rubber binding flexors for Rottefella bindings. Fits in Xcelerator Pro, Xcelerator 2.0, Xcelerator Junior, Sport Screw, Roller Ski, Performance, and all MOVE bindings. Comes in 3 stiffnesses: Soft (Grey), Medium (Black), and Hard (White). Xcelerator flexors are very easy to swap out! Simply push down the front white tab, and slide flexor backwards.