Here's what other sites are saying:
Your river safety kit is not complete unless it includes the Harmony 70 Foot Rescue Throw Bag. All 70 feet of the floating polyethylene rope are stuffed into a tough Cordura nylon sack, which is equipped with carry handle and quick-detach loop for securing the bag to your boat. Clip it on to your deck and you're ready to head out. You might want to make sure your buddies each have one, too, in case you're the one doing the swimming.