Croakies Terra SystemSunglass Strap The Terra System is Croakies newest eyewear retainer.The Terra System combines the light weight and adjustability of the classic Terra Cordswiththe interchangeable end technology of the ARC family. The Terra System features the same durable Terra climbing rope. The XXL Terra Ends fit big, bulky frames, and the extra XL Terra Ends will fit medium to large frames. Each side is 12 inches long.