All C4 WATERMAN iSUP products are fabricated from heavy-duty, military-grade, double-wall PVC material. Inside each product, thousands of high-tech fiber ‘cilia’ anchor the deck to bottom, allowing for superior rigidity and locking in C4’s proprietary rockers–features that grant never before seen durability and the closest thing to hard board performance of any inflatable surfcraft. And unlike the other brands that use only glue on their seams, the iWATERMAN products are finely stitched with 30% additional thicker, high-tensile fiber thread, making them much tougher, stiffer, and able to withstand a higher PSI (pounds per square inch) of inflation, ranging from 14 -17 PSI. The result: A rough-and-ready surf/paddle/rescue tool that is pliant enough to bounce off rocks, yet still deliver hard product performance and reliability.