Introducing Spitfire’s newest soft 90 Duro cruiser wheels, the Sapphires. A newly developed 90DU clear riding surface, bonded to a 101DU Formula Four inner core, gives you fast, smooth, long-lasting speed wherever you choose to burn. Features: Diameter: 53mm Durometer: 90a 90DU Clear Riding Surface Bonded to 101 Duro F4 Inner Core Fast and Smooth Long Lasting Speed