The O’Neill Comp Vest lineup defies convention and sets a new industry standard for performance driven technology. The lightest vests in the water just got lighter, stronger and dry faster than ever. Nytrolite Foam Technology. Low Density Polyethylene which is expanded using Nitrogen in an exclusive process which cannot be duplicated. 3x lighter than PVC foam. Closed cell foam structure that absorbs 15-20% less water. Approximately 10% more buoyant than PVC meaning we can use less foam in each vest and it will still float the same.