Upgrade your bicycle's performance with these premium ABEC-7 rated ball bearings. Featuring precise 17x30x7mm dimensions and blue rubber seals, these bearings are engineered for superior smoothness and durability. The double-sealed 2RS design provides excellent protection against dust, dirt, and moisture intrusion, ensuring consistent performance in various riding conditions. Perfect for both front and rear bicycle hubs, these bearings deliver whisper-quiet operation with minimal friction, enhancing your overall riding experience. The high-precision construction maintains tight tolerances for optimal alignment and rotation, while the robust design stands up to regular use. This set includes 4 bearings, giving you everything needed for a complete hub upgrade. These versatile bearings combine smooth operation with reliable performance, making them an excellent choice for cyclists seeking quality components for their bikes.