Purchased 3M EX550 frames as arms on old ones were busted off but Rx glasses ok. At a tad South of $60 with all costs applied I thought this was a good deal. I was mistaken. The first lens went in absolutely perfect, but the second lens did not as the screw was frozen and would not back out even with excessive force applied. This is a DEFECT, and frankly makes me wonder about 3M quality control... sigh, the new frames along with old ones and expensive Rx glasses are now in trash. UPDATE: I was pleasantly surprised to have received a call from Simply apologizing for defective frames and when I told them that I had already thrown them and Rx glasses away was offered 50% off a new Rx! I did not take them up on it as I felt that was over-board - I am not looking for handouts, just want what I paid for. At any rate I thought it was well above average these days for someone to call back and try to make things correct. Since I am seriously thinking I will give them (Simply...) another go I can not argue for anything less than 3-stars but not quite 5-stars given defective frame issue. If I buy from them again I will provide another rating based on that experience.