Model Number: DCA0021 Brand Name: OEM Key Specifications/Special Features: DescriptionAbout the product1. This adapter is able to adapt your smaller lens to bigger lens, make your camera more powerful, which allows you to have more purchasing choices of lens.2. The internal diameter is 52mm; the external diameter is 67mm.3. High quality metal material, lightweight and portable.Specification:Material: aluminum alloySize: 52mm-67mmWeight: 7g