KEY FEATURES V Back section adds stretch where you need it most for a secure fit and maximum range of motion BioLite Construction is lighter than neoprene improving comfort for long term wear Youve got to wear a vest if its going to help you so the OBrien Flex V Back Mens Life Vest is designed to be as comfortable as possible for the wearer BioLite construction offers a significant weight reduction compared neoprene construction methods while still offering exceptional comfort in or out of the water The Hinged design includes a V Back design that introduces a bit of stretch to give you secure fit that maintains your full range of natural motion