Well, after reading the other reviews I decided to TRY these out against my better judgement. You can write just fine with the overlay applied. There is no problem at all on my M505. However, seeing the screen is a bit tough. Not sure what type of materials they use, but I would think they could find something a bit more transparent. I would recommend that you do NOT buy these overlays. The lack of clarity is reason enough. Application was a breeze though... :)