A. This mountain bike crank locking screw features an integrated hollow crank fixing design and is made of metal, ensuring reliable quality. It is suitable for users of all genders, with a wide range of audiences. B. The specification is M6x18 per set, and each set contains 2 pieces, which can meet the fixing needs of bike cranks. Whether you're riding daily or exploring the mountains, it can provide stable crank locking for your bike, making your ride safer and smoother. C. This product has an authorized private brand. Although it is not an imported product, its quality is comparable. It is not designed for children and is a suitable accessory for adult mountain bikes. D. It is favored by consumers in many regions around the world. The main sales regions include Europe, South America, Southeast Asia, North America, Northeast Asia, and the Middle East. It is also popular on many major e - commerce platforms, such as eBay, Amazon, Wish, AliExpress, independent websites, Lazada, and Shopee.