A cowstail is a length of rope, webbing, or accessory cord with a loop on each end. A daisy chain can also be used. One loop attaches to the carabiner on your harness, and the other loop has a locking carabiner on it. A cowstail can be used for many things including:
Often, a short and a long cowstail are tied side by side to offer more versatility. When you're not using your cowstail, simply wrap it around your waist and clip the carabiner to one of the gear loops on your harness.