Adorama Lens Reversing Ring for Canon EOS Auto Focus Lenses with a 58mm Filter Thread.
Reverse Rings are threaded on one side to fit the filter thread of your lens. The other side has a mount like your camera lens. Screw the adapter into your lens' filter thread, turn the lens around and bayonet it into the camera body. This greatly increases the macro reproduction range capabilities. Although the lens will fit physically, automatic diaphragm, auto-focusing will not operate