Chums Rope Slip Fit 3 mm Solid Eyewear Retainer is field tested and guaranteed to keep your glasses in place. Chums' patented Universal Fit tips are molded directly to the cord and will accommodate a wide variety of eyeglass frames. Nylon 3 mm cord utilizes perlon climbing rope construction giving itstrength, durability and style. Not recommended as tie-offs while climbing. | Chums Slip Fit Rope Eyewear Retainers