1. This is a bottom bracket fixing screw suitable for mountain bikes and 412 folding bikes. The screw is made of metal, specifically titanium alloy. This material ensures that the screw has good quality and durability, can withstand relatively large pressure and friction, and is not easily damaged even after long-term use. 2. Its specification is square hole M8x15mm. The precise size design allows it to fit the corresponding bicycle models well, and the installation process is easy and convenient. In addition, this screw has a waterproof function, which can effectively prevent moisture from entering, avoid performance degradation and shortened service life caused by rust and corrosion, and ensure the stable operation of the bicycle bottom bracket. 3. Whether you are facing complex and changeable road conditions during mountain cycling or performing frequent folding operations during the daily use of a folding bike, this screw can play an important role, providing reliable support for your riding and making you feel more at ease when cycling. 4. It is suitable for multiple sales regions, such as Africa, Europe, South America, Southeast Asia, North America, Northeast Asia, and the Middle East, and can show good performance in different environments. In addition, it has an authorized self-owned brand, and its quality is trustworthy.