Ultra lightweight thermal. The Boulder Thermal Shell isolates you from the wet and cold, with its warm, ultra lightweight thermal insulation, full-length stormflap, and PFC-Free water repellent finish on the main body, comes standard with envious heat-seekers. The chin saver and adjustable hem with drawcord complete this fashionable functional thermal shell. Add to this the chin saver and adjustable hem with draw cord, and you really can’t blame them.