I have used Chums for many, many years and have found them to be a blessing each time I get a new one. I first started using neoprene strap on my first work glasses. They were washable and cleaned up nicely. I had them for about four years ands got somewhat tattered using them all day, all week in the sun on my construction sites. I eventually went to the narrow cotton ones for my slimmer temples on my new glasses and have purchased many different ones that were taylor made to fit snugly.
Cheaper brands just don't stand up to the daily wear-and-tear as Chums do. When you are ready to order, just check the ends of the temples on your glasses. If the ends are small or narrow, medium or large, purchase accordingly. Try them! You will not be sorry!