Costa Loop Retainer: The Costa Loop retainer is a minimal retainer designed for sunglasses with larger temple holes. The molded center clasp separates to thread through the end loops for secure, all day hold. From end-to-end, the Costa Loop Retainer measures 20". The Costa Loop Retainer is compatible with all Costa sunglasses. Born on the water in 1983: Costa Sunglasses for men and women is celebrating 40 years of making the premium sunglasses on the planet and protecting the watery world we call home