This wide-angle converter screws into the 28mm filter thread of Nikon's Coolpix point and shoot cameras and multiplies the focal length by 0.63; so a 38mm equivalent lens becomes 24mm, a reasonable wide angle for most purposes.
When I received the converter I was impressed by its solid construction: the exterior is all metal and there are four glass elements, which make it surprisingly heavy for its size. Later I subjected it to the accidental drop test (three feet onto a hard surface) and it suffered no harm, optically or cosmetically. It feels far more substantial than the average DSLR lens.
There is a front screw thread, so should you wish, you can attach a 72mm filter. Nikon advise using a thin filter to avoid vignetting. Remember though that while the effective focal length is 24mm, the actual focal length is much less than this, and as with all lenses of focal lengths less than 10mm there is an intrinsic polarizing effect without filters, so I found no need to use a circular polarizer. Another piece of good news is that conversion lenses do not affect the maximum aperture. So on the Coolpix 4500 this converter is an effective 24mm f2.6. It was very convenient to be able to carry the conversion lens in one pocket and the camera in the other. If only Nikon still produced a compact camera of that quality, but with a more modern sensor...
As you might expect, there is obvious barrel distortion at 24mm, if your subject has straight lines, but this is correctable with Photoshop. Chromatic aberration is not a problem, though some would probably be visible if I examined the images at 100% magnification. The converter was supplied in a cute little velvet bag, with front and rear screw-on lens caps.