?FEATURES: Super Light (SL) headset bearings are 25% to 38% lighter than conventional bearings and offer similar durability SL bearings use a steel inner race and ball bearings with an abbreviated outer steel race housed inside an alloy shell Sold individually SPECS : Color: Red Weight: 20.6g Bearing Type: Angular Contact Sealed Cartridge Angle: 36°x45° OD: 52mm ID: 40mm Thickness: 7mm