Each of the four models in the STAR SELECT SERIES is fully wrapped up to the side strake with an additional layer of 1100 denier fabric. The heavy-duty 1.8mm 4000 denier floor material is the toughest in the industry. StarTrack wear patches extend from bow to stern on the bottom runners for added protection. Extra D-Rings have been added for your convenience. For the Select Series we have used the maintenance-free Leafield inflation. The self-bailing floor, with heavily reinforced drain holes on the sides, is permanently attached so there are no bulky ropes or time-consuming lacing. New for 2009!!! Our floor design consists of a drop stitch bladder! The advantage of a drop stitch floor is that it is flat and rigidand since it is made for higher pressure, you don't have to be as careful about over inflation and no release valve is necessary.