This is the 5/3mm Akona Super Stretch Hooded Vest for Scuba Diving Features: Most Comfortable Hooded Vest You&';ve Ever Worn Give Layering for Added Warmth Layering Increases Bottom Time and Comfort for Multiple Dive Days Staying Warmer May Reduce DCS Potential 4-Way Quantum Stretch Neoprene Hood and Vest 3mm Vest 5/3mm Hood Glued and Blind Stitched Seams Glide Skin Face and Neck Seal Unique Rubberized Neck Panel Matches AKONA Suit Seal Custom Trim-Able Face Seal The Akona Quantum Stretch Hooded Vest is made with 4-way stretch neoprene that gives the most comfortable fit you have ever worn. A unique rubberized neck panel and an exterior seal provide warmth and reduce the amount of water entry. Combined with an Akona wetsuit, the hooded vest works perfectly to create a glide-skin neck seal which prevents water from seeping in between the suit and the vest. All this means more comfortable and enjoyable diving!