The bottoms of tubes are also covered with an additional layer of the same 1.5mm PVC. * Round end tubes provide more buoyancy and support for heavier engines. Transom holders are re-enforced with additional layer of PVC to protect against UV-rays. * Two lifting D-rings added inside front bow for the securing of additional equipment. * Air valve of air floor is protected with a cover to keep dirt and water away. * Premium AM boats are made by Saturn Inflatables for European market. New 2013 version of Azzurro Mare AM330 comes with FREE boat tubes cover to protect boat from damaging UV rays and to extend boat lifespan. That is over $600 in value added package. Azzurro Mare boats are of exceptional quality workmanship and covered by 5 years warranty against manufacturer defects of hull and transom. 11" AM330 boat is great as a ship-to-shore dinghy or tender for main ship. 5 Year Manufacturer Warranty for transom and hull seams on all AM boats. Attractive Euro-style squared shape bow adds more useful space in front. The V-shaped bottom of AM inflatable boats is made of Extra heavy-duty 1.5mm PVC, which is almost twice of thickness of heavy-duty 0.9mm (1,100 denier) PVC.