The Woobie JacketRip Stop Nylon Shell 100% Polyester Active Insulation Durable Water Resistant (DWR) Coating SIZING: IF YOU ARE BETWEEN SIZES, SIZE DOWN The Woobie Jacket utilizes the same material as the classic Woobie Blanket, so it features the same lightweight, packable, and insulating layer that's abrasion resistant and dries quickly. The Woobie Jacket is the perfect mid layer to keep you comfortable on the move and in camp.