Khiro S-Cone/L-Barrel Skateboard Bushing Set 95a Hard Black
The typical skateboard truck has two bushings on each truck. Bushings are rubber rings found inside the trucks that cushion the trucks when a skateboard turns. The stiffer the bushing the more stable the board. The softer the bushings the easier it is to turn a skateboard.
Be sure to change your bushings frequently in order to keep your skateboard responsive to your personal skateboarding style.