Lightweight Black Nylon Sports Neck Cord/Retainer for Sunglasses or Spectacles Suitable for Both Metal and Plastic Framed Eyewear and Can Accommodate Virtually Any Pair of Eyeglasses Total Length 60 cm with a Cord Width of 10 mm Flat Adjustable Looped Rubber Ends Approximately 10 mm x 5 mm Maximum Just Slide the Loops Over the Arm Ends and Squeeze the Metal Clasp Until the Loop Grips Each Arm Firmly, Then Adjust the Toggle for a Comfortable Fit Once On Your Head.