I have quite a few M-Frame lenses in various shapes and colors, a M-Frame Pro frame, and an SI M 2.0 frame. I haven't used them for a while since my prescription changed. I happened upon a solution to put my M-Frames back into action. ESS sells an oakley adapter for their behind-the-lens prescription adapter. I purchased two (for different prescription uses), quickly checked that they would work, and took them down to my optician to have the prescription lenses installed. A quick check suggested that the nose piece adapter would work. But later I realized that it does not fit. At some point in time Oakley moved the lens retaining tabs up the lens. Oakley currently has a sale so I purchased a new lens. The ESS nose piece adapter fits the new lens. However, the new lens does not fit any of my frames! In addition to the nose piece compatibility issue, the ends of the lens that fit into the frames notches are different and this lens does not fit either of my frames. The new lens may be slightly wider as well. Despite numerous posts on the internet suggesting that there is wide compatibility between the three parts of the system: 1. frame, 2. lens, 3. nosepiece among Gen 1, 2, and 3, this is not the case. There are a lot of differences. I have looked for videos and webpages for a comprehensive list of compatibility but most are incomplete and/or misleading. Does anyone in this forum have a resource that could help?