LR 604 NPP Custom Ball Bearings Features:   1. The product's outer circle is processed into a R500 arc surface (model suffix belt U), which makes the product bear good force in the process of using. 2. The inner structure design and thicker outer ring of deep groove ball bearing or double row angular contact bearing are adopted to make the roller have higher load-carrying capacity. 3. Rollers are made of high-quality bearing steel, heat-treated, precision grinding and filled with long-life high-quality multi-purpose grease.   LR 604 NPP Custom Ball Bearings Advantages:   1.Small resistance, long life and wide application 2.Easy to install 3.Smooth operation and small error