Although the strap works well,
"Although the strap works well, the real issue for me is the glasses themselves. Although I have not written my review yet, here is the problem in a nutshell. It is impossible to insert the different lens on the additional frame provided. I have watched the videos etc, and it will not snap onto place regardless of the amount of force that I apply, which has been considerable. The slot is simply too small. I would return them to Amazon, but it looks like I have lost the box, so I presume I can't return them. I will prepare a more detailed internet review soon."