20 Pack Full Ceramic Miniature Bearings 684-2RS Sealed Si3N4 Ball Bearings 4x9x4mm, PTFE Cage, High Precision, Low Friction For Hobby, Robotics, CNC, And Precision Machinery Ideal For Micro Linear Guides, Drones, RC Models, 3D Printers

These sealed full ceramic bearings are lightweight, ultra-precise parts designed for hobby, robotics, and small machinery. They handle high speeds and harsh environments where corrosion resistance matters.

✅ Bearing type: full ceramic 684-2RS sealed
✅ Ball material: Si3N4 ceramic
✅ Cage material: PTFE
✅ Inner/outer races: Si3N4 ceramic
✅ Dimensions: 4x9x4 mm (ID 4 mm, OD 9 mm, width 4 mm)
✅ Pack size: 20 bearings per pack

💡 What is a ceramic ball bearing used for? Ceramic bearings are handy in tough environments. They provide fast, smooth motion with reduced heat and corrosion risk. - Ideal for high-speed spindles and precision gear work - Great for non-magnetic, clean-room setups - Helpful in wet or acidic conditions