Description: Aluminum Alloy Material: Bearing headset adopting aluminum alloy, durable to use. Flexible Rotation: high-grade bearing, silent, flexible rotation, very lubricated Electroplating Surface: Internal sealed bearing with its surface electroplating polishig. The sealing ring is good for keeping dust and water away to prolong service life. Easy to adjust the bike's steering system after installation. Great replacement for the worn headset that was not steerer smoothly and evenly. Specification: Material: 6061 Aviation Aluminum Alloy, Premium Bearings Process: CNC Size Chart: 44-44MM Black1: 44x44x30mm/1.73x1.73x1.18 inch, for 28.6 Straight Fork; 44-44MM Red: 44x44x30mm/1.73x1.73x1.18 inch, for 28.6 Straight Fork; 44-44MM Black2: 44x44x40mm/1.73x1.73x1.57 inch, for 1.5 Cone Fork; 44-50.6MM Black1: 50x50x30mm/1.97x1.97x1.18 inch, for 28.6 Straight Fork; 44-50.6MM Black2: 50x50x30mm/1.97x1.97x1.18 inch, for 1.25 Cone Fork; 44-50.6MM Black3: 50x50x40mm/1.97x1.97x1.57 inch, for 1.5 Cone Fork; 44-50.6MM Black4: 50x50x30mm/1.97x1.97x1.18 inch, for OD2 Straight Fork; 44-50.6MM Black5: 50x50x40mm/1.97x1.97x1.57 inch, for OD2 Large Cone Fork; 44-55MM Black: 55x55x40mm/2.17x2.17x1.57 inch, Universal Version of Straight Fork and Cone Fork; 44-55MM Red: 55x55x40mm/2.17x2.17x1.57 inch, Universal Version of Straight Fork and Cone Fork; 44-56MM Black: 56x56x30mm/2.2x2.2x1.18 inch, Universal Version of Straight Fork and Cone Fork; 41.8-52MM Black: 52x52x30mm/2.05x2.05x1.18 inch, Universal Version of Straight Fork and Cone Fork; 41.4-41.4MM Black: 41.4x41.4x30mm/1.63x1.63x1.18 inch, for 28.6 Straight Fork; 44-52MM Black: 52x52x30mm/2.05x2.05x1.18 inch, Universal Version of Straight Fork and Cone Fork; 34-34MM Black: 34x34x30mm/1.34x1.34x1.18 inch, for 28.6 Straight Fork. Package Includes: 1 Piece Bike Headset