CANON 2X EF Extender III
The Canon EF 2x Extender III is Canons newest teleconverter for use with Canons L series telephoto lenses. The Extender III provides a two times extension of your lenses current focal length, while only reducing the amount of light by one stop. This Extender is perfect for use with our Canon EF 70-200mm f/2.8 L series lens.
A full list of compatible lenses is available here.