Rollerblade's Hydrogen Wheels are the pinnacle of performance. When speed is your game, the 110mm wheels are the ones you want spinning underneath your feet. Now with this 8 pack you'll have 6 wheels at 110mm and 2 at 100mm so that you maximize your performance by using the smaller wheel in the second position. The Hydrogen Wheels deliver power and response with more grip to keep your steady and longevity for greater use. The urethane is a great vibration reducer which means less fatigue and more performance for longer stretches. The core of the Rollerblade Hydrogen Wheels are designed in a way to give you more flex, power and energy with each stride. These premium wheels are a must-have for the serious skater looking for that performance. Skate Type: Fitness, Best Use: High Performance, Bearings Included: No, Number of Wheels: 8, Wheel Durometer: 85A, What Bearings are Included?: None, Model Year: 2019, Product ID: 340583, Model Number: 06230100 000, GTIN: 0885315822017