The Hellbender 70 bottom bracket utilizes bearings made of 440C stainless steel providing exceptional ride quality and reliability while striking a perfect balance between value and lasting performance. Marine-grade grease and robust bearing seals complete the package in terms of durability.440C stainless steel bearings with a dual lip seal and marine grease offer durability and corrosion resistance6061 T6 machined aluminum cups are lightweight and durable TECH SPECS Bottom Bracket Shell I.D. 1.37 BB/Frame Interface English BB Shell Width (mm) 73 Weight 92 Defined Color Blue