Is an expertly fabricated aluminum rack that mounts to your pontoon's ski tow bar with aluminum clamps that will. Mount to your ski tow bar (included). When you have The Matt RackT on your boat you reclaim. Your floor space to use as you want. The Matt Rack T safely stores your floating mat so that you can maintain complete visibility to the rear for the safety of your tubers, knee boarders, and skiers. To order we need to know 2 things. To determine your clamp size use the method below. If you are not sure what your tubing size is just use the directions here to calculate it. Use a piece of string or paper and wrap it around your tower tubing. Measure the amount of string or paper that it took to wrap around the circumference. Circumference (inches) = Diameter (inches). 3.927 = 1.250 (1 1/4). 4.712 = 1.500 (1 1/2). 5.105 = 1.625 (1 5/8). 5.498 = 1.750 (1 3/4). 5.890 = 1.875 (1 7/8).