Reverse Adapter for Pentax K Mount to Mount 49mm Filter Diameter Lenses in Reverse

Allows you to attach a 49mm filter diameter lens in reverse to a K-mount camera. Enjoy macro photography with ease. How about this as one way to utilize old lenses?

Lenses without an aperture ring are not practical for use, as they will be stuck at the minimum aperture.
Other manufacturers' lenses with a 49mm filter thread can also be attached. Please prepare lenses with aperture rings, such as Nikon or Canon FD.
Please be careful with heavy lenses, such as telephoto lenses, as the filter mount may break off.