Features 1、Built in deep gutter ball bearing and metal bearings, high speed, efficient operation, long lasting silent; insert the fork accurately, smoothly, bearing 360° rotation. 2、The integral seal, retain the lubricant within the bearing, the dust proof and waterproof effect is good, extending the service life, suitable for harsh riding in environments. 3、Outer bowl is made of aluminum alloy material with T6 heat treatment and CNC process, light weight with the unchanged strength as heavier one. 4、The weight of the bearing headset is about 125g/4.4oz, will not increase the burden or cause additional fatigue while providing convenience. Rubber waterproof ring, which is anti corrosion, waterproof and sediment proof, has longer service life. 5、The outer bowl is made of aluminum alloy material, T6 heat treatment, CNC process, and lightweight strength. Suitable for frame head tube upper pipe inner diameter 44mm/1.7in, lower pipe inner diameter 50.6mm/2.0in, OD2 small tapered tube front fork upper outer diameter 31.8mm/1.25in, lower outer diameter 33mm/1.3in . Item Type: Bike Double Bearing Headset Material: Aluminium Alloy Application: For Frame Head Tube: The Inner Diameter Of Upper Tube Is 44mm/1.7in And Inner Diameter Of The Lower Tube Is 50.6mm/2.0in. For Front Fork: OD2 Small Tapered Tube Front Fork Upper Outer Diameter 31.8mm/1.3in, Lower Outer Diameter 33mm/1.3in. Weight: Approx.125g/4.0oz Specification: 44-50.6mm/1.7-2.0in (With OD2 Small Tapered Fork) Package List 1 x Sunflower Shape Top Cover Kit 1 x Headset Cover 1 x Pressing Ring 1 x Upper Bearing 1 x Upper Bowl Set 1 x Lower Bowl Set 1 x Lower Bearing 1 x Bottom Gear