Bluemoona 100 PCS - Multi-Purpose Glasses Rope Spare Rubber Ring Spectacle Chain Cord Ends

The rubber is of a smaller diameter than I expected. Not bad, but as they are, they have less grabbing surface, the cinch wire tends to slide, and they are a little stretcher than I wanted. Overall, each of these problems diminishes with thicker rubber rings. As a result, these tend to loosen under normal use even when cinched tight. These likely work best with large limbed glasses.Each piece is very consistent, the rubber works and appears durable, and overall, these appear to be good quality. They work for holding the glasses once on a tie as advertised. I've been using 2 of them for a couple of weeks and they continue to work for me with the limitations noted.