This is a precision machined adapter made for the Canon S100 digital Elph cameras. They screw into the tripod thread of the camera and offer a 28mm thread for the addition of 28mm and larger lenses/filters. 28mm Filters - UV, Polarizer, ND4, Sky1A - you can also use larger filters with the use of step-up rings. 28mm Lenses - Nikon TC-E2 2x, TCE3 3x,WCE63 .66x, FC-E8 fisheye, .42 titanium w/ macro. We have many other lenses that work with this adapter also. See lenses. Key Features *Screws into tripod thread & offers a 28mm thread for the addition of 28mm and larger lenses/filters.Buy ?