These leashes help stop your fins from coming off during the session to prevent you from losing them. The new adjustable buckle has a clip opening, making it easier and quicker to put the leash on, without having to tighten it every time. Open the buckle before putting your foot into the fin, then close it by passing the strap over the foot. Make sure that it is sufficiently tightened before going into the water, so that your fin stays in place.