Features:brand new and high qualityIt helps to isolate and dampen shock and vibration as well as has a long service life.Made of high quality material with a black coated finish, aluminum alloy hardware and rubber balls.This base, as phone and camera holder, is suitable for many motorcycles, bicycles and other vehicles.This design of the item allows user to mount to just about many things on your motorcycles.This is a motorcycle mirror frame base with 20mm hole. Specifications:Material: Aluminum Alloy+RubberColor:Black Hole Diameter: Approx. 20mm/0.78 inchesBall Diameter: Approx.25mm/0.98 inches Note:1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes:1x Ball for Head Adapter