The SRAM GXP BlackBox Bicycle Bottom Bracket features two ceramic balls which are lighter and more efficient than standard bearings, as well as being resistant to dirt and moisture. Utilising gutter seal technology, the bracket also reduces friction and drag to improve feel and performance for the rider. - L.M. Features: SRAM GXP BlackBox Bicycle Bottom Bracket 2 lightweight ceramic balls More efficient than standard bearings Resistant to dirt and moisture Gutter seal technology to reduce friction and drag Stainless steel races and high-polish cups Helps you to reach terminal velocity quickly Weight: 105g (Manufacturer claimed) Material: Ceramic Balls/Stainless Steel Races Compatibility: GXP Cranksets Availability: English threading