Material: Aluminum Alloy. Color: Black/Red/Gold/Silver. Size: 60 * 22 * 18.5mm. Net weight: 17.7g. Gross weight: 25g. Packaging: 1pc* bicycle flower drum quick release lamp holder. Advantages: Protects rear shift transmission when bicycle accidentally rolls over. Allows installation of warning light for additional safety during night riding. Can be installed on front wheel to free up space for handlebars and reduce light height.