Rollerblade Hydrogen 110mm 85A Wheels, 8 Pack WHEELS ARE MEASURED in mm (height size) and A (durometer/hardness). A higher "mm" number means faster wheels. A higher durometer "A" number means harder wheels. Harder wheels last longer. 110mm/85A PREMIUM FORMULA with incredible resilience, roll and rebound. CONSISTENT SPEED, CORNERING AND PERFORMANCE are achieved through the solid core design. The scooped core feature properly bonds and supports the urethane to enhance the skate experience. MAXIMUM GRIP, WEAR AND VIBRATION REDUCTON come from the proprietary urethane formula. MADE IN THE USA, 8 WHEELS PER SET (bearings and spacers not included)