Features: Waterproof bottom bracket nuts for mountain bikes can effectively prevent water, sand, dust, etc. from entering the bottom bracket, effectively increasing the service life of the bottom bracket. Mountain bike road bike dead-speed bottom axle steel waterproof screw, diameter 8mm, suitable for ordinary square hole bottom axle, bottom axle is not suitable, use two screws on bottom axle Specifications: Material: Steel Weight: about 13g Application: Bicycle square hole central axis Suitable for 8mm Allen wrench Package Contents: screw*2 【High Quality Materials】We use high quality materials to manufacture our products to ensure their quality and durability, and we are committed to providing excellent product quality. 【Sturdy and Practical】Our products have been rigorously tested and verified and have excellent durability and practical functions. No matter when and where you are, our products will consistently provide you with reliable performance and service. 【Easy to Use】Our products are simple in design and intuitive to operate, making them easy to use even for novices. We focus on user experience and hope you can enjoy the use process easily. 【Provide you with help and fun】Our products are designed to provide you with help and fun in your projects, our products will be your right-hand assistant, bringing you a pleasant and satisfying experience. We look forward to your choice and are willing to share this fun with you. 【Excellent After-Sales Service】No matter what problems you encounter, we will solve them for you in time to ensure your satisfaction and shopping experience. If you have any questions about the product, please contact us and we will respond to you within 124 hours.