Working with our ambassadors and many of the world’s best big-wave riders, our R&D team developed the PSI (Personal Surf Inflation) Vest to help increase safety in the heaviest and most hazardous surf. The Men's PSI Vest is fully backed by our Ironclad Guarantee and you can find it on Patagonia.com. | Patagonia Men's PSI Surf Vest in Mojave Khaki, Medium - Nylon/Spandex