By far the most smoothest wheel in the scooter industry and ideal for hitting the park. River Wheel Co. Sapphire Glides in 110mm Wheels feature Buff Core Technology to reduce dehubbing. All River Wheels come with bearing removal slots for taking bearings out with ease. These wheels come with High Quality River Flash Flood Bearings Pre-installed! All River Wheels come with a 90-day Warranty against chunking. Anodized 6061 T-6 Aluminum Core for Durability. 100% Made In the California.