All mountain direct set features bearing steel 28-ball retainer top bearing, 34-ball max bearing lower.

Features:
• Weight 65.5g 
• Size 1 1/8in. 
• Stack height 21mm including crown race 
• Material 52100 bearing steel 
• Preload aluminum/steel 25g 
• Upper bearings sealed 28-ball retainer 
• Lower bearings sealed 34-ball max 
• Warranty 5 years