The Canon Extender RF 2x is the best choice for photographers who want more zoom range with their RF lenses. As the focal range is extended by a factor of two, it is ideal for sports, nature and reportage photographers. The extender features high-refraction, low-dispersion glass to control field curvature and chromatic aberration, for maximum image quality. In addition to optimized lens coatings, a three-layer combined lens helps reduce ghosting by minimizing surfaces that come into contact with air. The exterior is coated with the same white thermal shield coating used on the RF 100-500mm F4.5-7.1L IS USM and RF 70-200mm lenses, to prevent deterioration when performing at high temperatures. A mechanism that limits the zoom of the RF US 100-500mm F4.5-7.1L IS USM zoom range (300 to 500mm) prevents the lens elements from hitting those of the extension. The extender is designed for reliability and durability with shock resistance and dust and water resistance, for use by professionals and more experienced amateurs. Features of the Canon Extender RF 2x More range without loss of image quality Suitable for extreme performance Perfect integration with the Canon RF 100-500mm F / 4.5-7.1L IS USM No compromise on construction Compatible with: RF 100-500mm F4.5-7.1L IS USM RF 600mm F11 IS STM RF 800mm F11 IS STM Resistant to shock, dust and water In the box Canon Extender RF 2x RF Extender Cap RF Lens Cap LP811 Lens Case Manual Two Year Warranty