more info here SIZES SAFTEY BELT / ONE SIZE ITEM NO. AE-IV105 NEW/ 2021 New release 50N PVC bladder Waist belt pack HARD FACTS/ Waterproof and lightweight nylon Low profile slim design offers comfort and freedom of movement Pull-cord inflation with oral inflation backup D-ring clip point for extra attachment ISO 12402-5 50N air bladder with refelctive panels Compatible with 16g CO2gas cylinder Stone grey color KEEP YOU AFLOAT Safety is always a priority for us at AZTRON. Wear this lightweight, compact and stylish Safety Belt Pack around the waist, and enjoy a peace of mind.