This is not a free Freight itemThe 4D is a modify of the 3D tower except with 2.5 diameter lower leg tubing the billet aluminum plates for a more custom look. This looks amazing on any boat and will adjust for almost every boat out there. Designed with 8 welded cross gussets, this makes the Air Tower design unbeatable in quality, function and strength. No tools required for folding. Comes equipped with integrated folding lever. State of the art pivoting mounting feet, make mounting on any angled surface now a reality. One ' threaded stud per foot equals no connect the dots, gel coat cracks. Pivots forward for garage storage and is never higher than 29' off mounting surface. Stainless hardware and bolts to insure against all weather conditions or galling of threads, an important factor often overlooked. The adjustable version telescopes to accommodate almost any boat. Every thing is rigid and rattle free. Air Tower and all hardware included are UPS shippable.