Specifications: Nut Shaft Diameter: 9.9mm, Bolt Head Diameter: 8mm, Nut Shaft Length: 6.5mm/8.6mm/12.9mm, tailored for fix single/double/triple chainwheel. Robust Carbon Steel Construction: Crafted from quality carbon steel, ensuring sturdiness, lightweight performance, corrosion resistance, and prolonged durability. Easy Installation and Removal: Effortlessly secure and detach these bolts, simplifying maintenance and adjustments on your bike. Ideal for: Enhancing the stability and security of your bike's chainrings, ensuring a reliable and safe riding experience. Versatile Compatibility: Suitable for mounting chainrings onto cranksets, compatible with a wide range of bikes including mountain bikes, road bikes, and folding bikes. Package Content: E.