M20 Suitable for 20mm diameter chainrings.Please Understand the Size You Need before Buying. The Size that Does Not Match Can Not Be Installed. High Quality: Made of aluminum alloy, the surface has been electroplated, high quality is excellent, anti-rust and anti-corrosion. Easy to Install: It is delivered with screws and can be installed on the chainring with an Allen wrench. Scope of Application: Wonderful accessory for bike chainwheel. It is used to fix the the crankset and crank of the chain wheel, which is a great accessory for cycling enthusiasts. Features: High Quality: Made of aluminum alloy, the surface has been electroplated, high quality is excellent, anti-rust and anti-corrosion. Easy to Install: It is delivered with screws and can be installed on the chainring with an Allen wrench. M20 Suitable for 20mm diameter chainrings. Specifications: Material: Aluminum Alloy Weight: 23g Size: 2.8cm Color: colorful Package List: 1X Crank Cover 2X Screws Note: 1.Please allow 1-2cm measuring deviation due to manual measurement. 2.Due to the different monitor and light effect, the actual color of the item might be slight different from the color shown on the pictures. Please Understand, Thanks!