This thermal emergency blanket was named The Best in tests by The Hammacher Schlemmer Institute due to its superior heat retention and durability. Designed by NASA, mylar blankets use self-warming insulation to retain up to 90% of one’s natural body heat and create a soothing warm environment without any electricity. Institute analysts determined that this blanket’s thermal mylar material prevented heat from escaping the longest—especially at below freezing temperatures—and resisted tearing and punctures better than other tested models. Includes four thermal foil blankets (each in its own drawstring bag) packed in a waterproof EVA case with a convenient carabiner. Weighing only 2 oz. and about the size of a wallet, the case fits in a glovebox, backpack, or pocket. Each blanket 60" x 84".