O'Brien Nylon 4-Belt Sport Life JacketThe O'Brien 4-Belt Sport Life Jacket is a durable personal flotation device that is Harmonized U.S. Coast Guard & Transport Canada Approved. This nylon vest has an extended size range that provides a more accommodating fit for easy sharing. It features a sturdy nylon exterior with a flexible foam core for added comfort. The 4 adjustable belts deliver an excellent fit while the big armholes allow for a wide range of motion ideal for any watersports activities. The O'Brien Nylon 4-Belt Sport Jacket is an affordable option for a multi-use, durable life jacket.Features: Sturdy nylon exterior; Flexible foam core; 4 Adjustable belts; Big armholes; PWC lanyard attachment ring; USCG & Transport Canada approved; Sizes Available: Small/Medium: Chest Size 32" - 40"; Large/X-Large: Chest Size 40' - 52"; Super Large: Chest Size 50" - 60"; X-Super Large: Chest Size 60" - 70"; To ensure a proper fit, O'Brien recommends the following: With your arms down by your sides, measure around your upper bod, under your armpits and over the fullest part of your chest and shoulder blades.