✔ Suitable for - Shaft diameter 5/8" and hubs wheels diameter 1-3/8". ✔ Material - Manufactured by chrome steel sturdy and durable. ✔ Seal - Keeps grease in, prevents impurities from entering and extends bearing life. ✔ Performance - Precise size, smooth and low noise operation, multi-functional use in multiple scenes. ✔ Warranty - Three months warranty, free refund if there is any quality problem during the warranty period. XIKE BEARINGS / POWER UNLIMITED TRANSMISSION