With an ergonomic shape and integrated aluminum coating, the hooded undervest is the most advanced undersuit available from Aqualung. The aluminum coating acts like a shield and reflects your own body heat back to you, keeping you warm during cold water dives. Enjoy a perfect collar seal, created when the glide skin seals with the internal skin of your wetsuit, keeping water exchange to a minimum. 2.5mm superstretch 4-way neoprene with aluminum coating between the inside lining and the foam to increase Collar in glide skin sticks to the internal skin neoprene of the wet suit and makes a perfect seal Anatomic shape for a great fit Environmental friendly features: neoprene free of P.A.H. (Polycyclic Aromatic Hydrocarbons), made from a non-petroleum based material, with REACH (European Uni standards) approved thread Attached hood offers a face seal to limit the water entries and G2 Vent Technology that allows trapped regulator exhaust bubbles to exit while keeping cold water out