Extreme Max Rubber V-Block for Transom Saver: Keep your vessel from floating away with the Extreme Max transom saver rubber V-block. Just place one behind each wheel of your trailer to stop it from rolling. This product is made from strong rubber that is safe to use around the water. This boat trailer accessory wedges underneath the tires to get a snug and secure fit. Just a few seconds to set it up can save you lots of aggravation in the long run. The product is light enough to carry but heavy enough to stay in place.