Drop Stitch is a pretty amazing material we're using to create the RADs and FAD. This material allows us to build inflatable items that can be inflated to optimum rigidity while delivering the most durable inflatables we've ever offered. This innovative material is called Drop Stitch and is achieved by joining two pieces of support fabric together with thousands of fine polyester thread lengths. Each thread is spaced evenly and all threads are the exact same length. Next an air-tight coating is applied to the top and bottom of the support material to ensure an air tight seal. The result is Drop Stitch Construction. Drop Stitch construction is capable of achieving levels of pressure equal to 20 PSI (Pounds per Square Inch).