1.Improved sealing: the swimming bladder is equipped with a manual inflation valve and a valve cap, as well as a rolltop closure and double layer airbags. These features ensure excellent sealing and water seal, which makes the inner content dry and protected from water damage. 2.Spacious size: with dimensions of about 28 x 60 cm / 11.02 x 23.62 inches before inflation and about 23 x 4550 cm / 9.06 x 17.7219.69 inches after inflation, the dry bag plenty of space. It can hold items such as clothes, mobile phones, wallets and more, so you can store your needs. the most essential when swimming. 3.Builtin waist belt: the swim bladder contains a waist belt and a userfriendly design..Just attach the belt around your waist, and the floating buoy floats next to you while swimming, ensuring easy movement and convenience. 4. The swimming buoy is suitable for a wide range of water sports activities, including swimming training, swimming, drifting, boating, kayaking, surfing, fishing and more, making it an essential accessory for various waterbased adventures.