Akona's 5/3 mm Quantum Stretch Hood is a warm and comfortable design with a large bib for double layering on the lower neck and upper chest area. The hood is 5 mm nylon II neoprene and the bib is nylon I skin-in" for reduced flushing and added warmth. The double covered vented top will allow trapped air to escape; yet will not allow water to enter for better insulation. The Quantum Super Stretch neck affords easy donning and doffing while the skin-in compliments the skin-in of the Akona suits virtually eliminating water exchange keeping you warm longer. All seams are glued and blind stitched for added warmth and durability.