I must say that the seller did not present this item properly. Presenting it as a "Lens for Canon EOS 1D, ... " naturally makes one think that this lens has a standard Canon EF mount, which it doesn't. It has a 52 mm thread and mounts not to the camera body but to the front of a regular lens. The phrase about "Professional High Speed Auto Focus" in Technical Details just adds to the misleading information as it supports the idea that it is an EF lens mounted on the camera body.
In the Technical Details they do write that "Adapters for 67mm, 58mm & 52mm Lenses Included" but I don't know how many people will understand that as, like me, many should think that this lens has an EF mount. Besides, the package shipped to me included only two adapters for 58mm and 52mm, there was no adapter for 67mm. And my main lens has a 67 mm fron thread, so I could not mount this lens. I have another telephoto lens with a 58 mm front thread. Of course it doesn't make sense to mount a wide angle extension on a telephoto lens, but just to try it I did that. It didn't produce a wide angle image, which is normal with a telephoto lens, no complaint about that. But the quality of the image was not good at all, it was far from being sharp in both "wide angle" and macro modes. Maybe, when mounted on a short focal length lens, it would result in a better image, but I could not check that because of the missing adapter. Will now contact the seller and try to get that adapter, then I will add the result to this review.
Addition. I have contacted the customer service and it appeared that they cannot ship the missing 67 mm adepter. So I am reducing my rating to just 1 star (before I gave 3). And have in mind that you should not buy this item if you have a lens with a 67 mm front thread.