Skate Out Loud Roller Bones Turbo Speed Derby Skate Wheels 92A COMPLETE SET OF WHEELS - Eight wheels, enough for a pair of skates VERY HIGH QUALITY MATERIALS - RollerBones Premium speed/derby wheel with an extruded aluminum hub and high end urethane material. The best hubs and materials available for roller skating. SUPERIOR ROLL AND SPEED. Some feel this is the best wheel on the planet for quad speed skating or roller derby on a wood indoor rink surface. 62mm SIZE - The most popular size for quad speed skating. In a variety of colors and durometers (hardnesses) to match your preference and skating style. GREAT FOR DERBY SKATERS OR FREQUENT SESSION SKATERS - This is a good wheel for quad speed skaters, derby skaters, or frequent session skaters with a real passion for skating. The higher the durometer (the number with the "A" after it) the harder/firmer the wheel.