Cablz® are unique in the way they do not lay on your neck distract you or irritate your skin. Perfect for fishing boating golfing running biking hiking rock climbing snow skiing snowmobiling or just enjoying the great outdoors. Made of surgical grade steel cable & industrial strength rubber. XL fits larger framed sunglasses.Monoz: The surgical stainless steel cable is replaced with blue monofilament.Zipz: Allows you to easily adjust your Cablz®.