Exquisite workmanship, precise heat treatment, high quality, easier to dismantle and assemble the bottom gear with opening mouth Inner diameter of bottom gear hole: 39.8mm 44mm ordinary straight tube frame with 1.5 tapered tube front fork external headset The inner diameter of the frame head tube is 44mm (common in aluminum alloy mountain bike frames, and there are also a few road frames with this size), with a 28.6mm straight tube front fork, or a standard 1.5 tapered tube front fork, with an external structure bowl Group! With this headset, you can use 44mm normal straight tube frame, with R7, , FOX 32 FLOAT/TALAS, TS8, Reba, Recon, SID and other standard 1.5 tapered tube forks, enjoy More strength off-road, Giant 1.25 small tapered tube front fork features: the outer diameter of the upper end of the front fork is 28.6mm, and the outer diameter of the bottom end is 33mm. Generally, it is the Giant ATX7 series and ATX8 series dismantling front forks. For details, please refer to the data characteristics. Name: High Strength 44mm External Bearing Headset Weight: 130g (with tapered tube bottom rail) Colour:black Material:Aluminum alloy Size:44 x 44 x 39.8mm Package Contents: 1 set x Bowl set Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.