Ergon GP1 BioKork Gripshift Bicycle Handlebar Grip Ergon's original and top selling grip and eliminates hand numbness and reduces upper body fatigue; for gripshift Supportive wing and comfortable Kraton rubber pad for optimal pressure distribution Sustainable cork rubber compound made from organic cork available in small and large with the size being the circumference between thumb and forefinger and six versions depending on shifters Forged aluminum lock on clamp for fast and secure installation