The award-winning MD3183 Deluxe Inflatable PFD with HIT (Hydrostatic Inflator Technology) is Mustang Survival's top-of-the-line inflatable PFD. Designed for serious users with exclusive technology that enhances safety and minimizes maintenance, this is our most popular inflatable PFD. The Hydrostatic Inflator Technology offers reliable inflation in a low maintenance design that will only automatically inflate when submerged in 4 or more inches of water and not inadvertently due to rain, spray or humidity. Exclusive to Mustang Survival in North America and maintenance-free for 5 years or until inflated. Made for the most severe marine environments the Deluxe Inflatable PFD with HIT will meet the challenges of the most demanding users. It also features the patented SecureZip™ closure system to ensure the PFD will stay closed during even the most rigorous activity and still opens effortlessly upon inflation. This lightweight and comfortable PFD can be worn over a T-shirt on warm days or over thicker garments in colder conditions. It is low profile and allows for maximum mobility. The neoprene Comfort Collar™ is soft on your neck and is part of a sleek design that is so comfortable you'll forget you're wearing a PFD. *Please Note: This product is a USCG Type ll and USCG Type V Commercial with Type ll performance when worn on uninspected commercial vessels less than 40 ft. in length and not carrying passengers for hire. Size Universal