A trade name used to denote ripstop fabric woven from polyester fibers. This results in a cloth that is somewhat lighter and more fade resistant than nylon ripstop fabric. The disadvantage I believe is the fabric is not as durable as normal ripstop nylona.

Modern sport kite sails are made from Icarex. There are basically 2 types of Icarex. Icarex polyester (P31/P38 - P31 being lighter) and the newer Icarex polycarbonate (PC31) which has a lower stretch rate and looks less crinkly. Icarex is now the preferred kite sail material rather than the older Carrington Nylon which is much heavier.