The Canon EF 2X II Extender doubles the focal length, enhancing telephoto shooting. - Model Name: EF 2X II - Included Items: Box, lens cap - Type: Extender I purchased this on Mercari a week ago. It's compatible with Canon EF lenses, but I realized after buying it that it's not compatible with the 70-300 lens, which is the only one I own... I was really looking forward to using the extender, so I was quite shocked, even though it was my fault for not checking. I only took it out of the packaging cardboard box and haven't used it at all since purchasing it. Since it's not compatible with my camera, I'm offering it at a bargain price. Thank you.