Product Name: Handlebar Plug with Light Product Material: Plastic + Self-expanding and shrinking elastic adhesive + Surface mount LED Light Product Color: Blue, Red, Green Please refer to the size on the picture when purchasing. It is suitable for cars with an inner diameter of 15mm or more. The principle is that the tighter the screw, the larger the aluminum ring on the handlebar plug will expand, making it larger, thus securing it and preventing it from falling out easily