The Promate Snorkel Vests are designed to allow you to swim with your head in the water as opposed to life vests that are designed to keep your head out of water. They are inflatable so you can add or subtract air to meet the level of bouyancy needed by the wearer. This vest also offers an adjustable waist and crotch strap in order to secure the vest in place with maximum comfort. Available in Day-Glo yellow, the snorkel vest should be considered a necessary piece of your snorkeling equipment. Size information: XL for about 240~320 LBS. Large (lg.) for about 150~240 LBS. Medium (med.) for about 80~150 LBS. Small for less than 80 LBS.