Features:Design has a bottom diameter of 8mm/10mm and a ball for head diameter of 25mm. It is suitable for most models and brackets and has a wide range of applications.Ball for head is made of rubber, and the screw is made of aluminum alloy, weatherproof, durable, rust-proof, durable and beautiful in appearance.screw adopts thread design and can be directly installed on the original rearview mirror of the car or where there is a screw hole, which is convenient and quick to install.Anti-skid and shock-proof, rough surface particles, increase contact area, not afraid of shaking.Easy and convenient installation, simple to start and easy to use.Specifications:Material: Aluminum Alloy + RubberColor: Black+SilverSize: M8/M10(optional)M8: Ball for Head Diameter 25mm, Thread Size about 10mm, Bottom Diameter 8mm, Total Height 5cmM10: Ball for Head Diameter 25mm, Thread Size about 10mm, Bottom Diameter 10mm, Total Height 5cmNote:Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order.Due to the difference between different monitors, the picture may not reflect the actual color of the item.Package includes:1 Piece Motorcycle Ball Clamp Base