What they say :

Features the innovative 3D vertical end seam along with tie-in points at the nose and three across the base of the bag, all of which are isolated from the air holding cell so that a tear out (a rare occasion at best) will be limited to the anchor. Also features a twist valve on the inflation hose and a high-capacity dump valve. 

Size: 30" x 29" (76 cm x 74 cm) 

Size: 43" x 32" (109 cm x 81 cm) 

Size: 48" x 32" (122 cm x 81 cm) 

Size: 55" x 32" (140 cm x 81 cm)