This premium hybrid ceramic ball bearing combines the best of both worlds with chrome steel rings and silicon nitride ceramic balls. The 6902 2RS bearing features precise dimensions of 15mm inner diameter, 28mm outer diameter, and 7mm width. The ceramic balls provide superior wear resistance and lighter weight compared to traditional steel balls, while the chrome steel rings ensure structural integrity. Both sides are rubber-sealed (2RS) to keep lubricant in and contaminants out. The bearing comes pre-lubricated with grease and uses a durable nylon cage to maintain proper ball spacing. Ideal for high-performance bicycle applications where reduced weight and enhanced durability are crucial. The ceramic construction offers excellent resistance to wear and abrasion, making it suitable for demanding environments where conventional bearings may underperform. This bearing provides smooth, reliable operation while maintaining tight tolerances for optimal performance.