1. Product Overview The 6904 open‑type thin‑wall deep groove ball bearing is designed for high‑speed rotary assemblies, offering ultra‑high‑speed performance and low friction.It is widely used in automation and precision machinery where lightweight structure and oil‑lubried operation are required. 👉 Get a quote within 24 hours for your project 2. Technical Specifiions Model 6904 Inner Diameter (ID) 20 mm Outer Diameter (OD) 37 mm Width 9 mm Structure Thin‑Wall Deep