The Apex Suit is powered by PrimaLoft® Cross Core™ insulation, which fuses best-in-class Primaloft Gold insulation fibers with aerogel technology. Originally developed by NASA for use in aerospace applications, aerogel is composed of more than 95% air and is the lightest solid material known to man. In its solid state, aerogel acts as a temperature barrier, locking out extreme cold and heat.