1、Premium Material: Adopting aluminium alloy material with T6 heat treatment and CNC technology, light weight and high hardness. Deep notch ball bearing ensures efficient operation and lasting silence. 2、Metal Bearing: Adopting metal bearing with 360 degrees rotation, which ensures high accuracy, high revolving speed and stable performance. 3、Dual Bearing Structure: Adopting dual bearing structure, easier and smoother to control handlebar. Integral sealing bearing can prolong service life and provide dustproof waterproof effect. 4、Rubber Waterproof Ring: This bike bearing headset adopts premium rubber waterproof ring, which is corrosion resistant, waterproof and dustproof, longer service life. 5、Reusable: This bike bearing headset is suitable for 28.6mm straight steerer fork, close and seamless installation, detachable and reusable. Item Type: Bike Bearing Headset Material: Aluminium Alloy and Stainless Steel Specification: 41/49mm (Suitable for Direct Mounting of Bearing on Inner Diameter of Upper 41mm and Lower Inner Diameter of 49mm) Cone shaped Head Tube Frame + 28.6mm Caliber Straight Steerer Fork with Bottom Gear) Bearing Specifications: Upper Bearing φ41 x 6.5h x 45 Degrees, Lower Bearing φ49 x 7h x 45 Degrees 1 x Top Cover Kit 1 x Headset Cover 1 x Headset Cover Loop 1 x Urgent Loop 1 x Upper Bearing 1 x Lower Bearing