This listing includes both the upper and lower headset bearings, two bearings included in sale.

For Giant Defy Advanced Pro bikes, compatible with all model years.

Upper Bearing - MR136

Lower Bearing - MR137

• GCR15 High Carbon Chromium Bearings: Chromium offers a corrosion resistance to the bearing, allowing you to get more use out on the trails and less time in the workshop changing bearings again due to rust and seizing.
  
• Buna NitrileRust Resistance Seals: Prevents moisture getting inside the bearing.
• Packed With Lithium Grease : Keeps the bearings running smooth and protected from the elements, grease also contains rust inhibitors and anti oxidants for further performance gains.