Trailer Lifts enable you to easily raise your boat above trailer bunks and rollers for bottom painting or trailer maintenance. The Brownell Boat Stands Trailer-Mounted Boat Lift is a safe, stress-free way to raise a boat weighing up to 7,500 pounds up to 12" above the bunks or rollers, by yourself. This allows you to easily apply bottom paint and do routine maintenance with your boat still securely attached to the trailer. This simple but ingenious system uses four lifts attached to your trailer and positioned under the four strongest areas of the boat: hull chines, stringers, and transom. While raising the boat, it's easy to keep the load balanced by turning the adjustable rod on each lift one half turn at a time. As your boat lifts up off of the trailer, it remains stable and secure because the lifts are attached firmly to the trailer itself. Sturdy, adjustable lifts are extremely easy to configure to accommodate a wide range of boat shapes and sizes. No more hoists or dangerous improvised solutions! Set of 4.