Maybe I got the only bad one.
I was in love with these for the first two days.  The design of the rubber grippers was clearly better than the standard noose-type loops found on other holders.  BUT...the rubber gripper split open on the third day.  Maybe there was a defect of some sort, or maybe the bows of my glasses were too wide.  I'm not really sure.  My refund was fast and without hassle.  I may buy them again and try them with glasses that have thin bows.  Other than the broken rubber end, they were of very high quality and packaged well.  I really wanted them to work.
Rating: 2 stars