Shortys Doh Doh 10 Pack box- Black 100a Skateboard Bushings Box Brand: Shortys Durometer: 100a The 100's are the hardest bushings made. Used by PRO's on the mega ramp so they don't get speed woobles, and also by very tall or heavy skaters. Best UPGRADE Bushings for Skateboarding and Longboarding. Turning trucks Better!