“Examining the K3s, they seem to be exceptionally well-made. I ordered an orange lens, too, and after inspecting the glasses, attempted to remove the factory lens, and replace with the orange lens. I followed the directions included with the booklet, with no success - I did not want to force the lens too much and break it. I even removed the soft nosepiece to see if that would make removal easier. I worked on it for about a half-hour, and gave up for the time being. Even went on Siroko's site to see if there was a video on lens removal. Went back to it a little later & tried manipulating the lens in different ways, and that eventually worked. I found that using a small tool to "pry" the lens away from the curve of the nosepiece solved the issue (getting the "tabs" of the lens away from the upper part of the frame wasn't an issue, removal from the nosepiece was the key, for me at least. Maybe I just got frames that were extra-tight; that is the only reason I didn't give 5 stars.”