The Fourth Element Proteus II sets a new standard for premium performance wetsuits. The suit is so warm that there is no longer a 7mm version of the Proteus. The Hexcore thermal lining in the torso area, in conjunction with the Hydrolock neck seal, offers unparalleled warmth. The plush inner lining ensures comfort and makes it easier to put on the suit. The highlight of the Proteus II is the internal half-vest connected to the suit. This additional neoprene piece is pulled over the head from behind once you are in the suit. This half-vest provides additional warmth to the torso and prevents water exchange through the back zipper.