Zealous Bearings are one of the most popular bearings in the industry. With built in speed rings and spacers at a precise .4045" these bearings eliminate all slop in your wheels for smooth rolling and predictable slides. They're lubed with nanoceramic grease that finds all of the small dings in the balls, fills them in, and corrects the bearings for a frictionless roll. This equates to a fast, smooth, and long lasting, self-fixing bearing. The steel ball bearings give you a fast and durable roll in an inexpensive and affordable price. For all styles of riding including downhill, freeride, or just cruising around, the Zealous Steel Built In Bearings are perfect for you. Precision 8mm axle holes 0.4045" built in spacers 0.5mm built in speedrings Green rubber seals to keep dirt and debris on the outside of the bearing Lubed with Archoil Nanoceramic Grease Extremely low water washout Corrosion on the inside of the bearing is nearly eliminated