Topsung Kids Deluxe Life Jacket Swim Trainers Arm Bands Rings Floats and Swim Vest for Children The design of hole is one-way inflatable to prevent air leak,if you want to vent the air, please hold the stomata. You could gasing expand by your mouth or pump. Please purchase from Topso to make sure the quality. There are three separate inflatable airbags with air holes,in case one of then leakage,other two airbags could be still normal use, it is safe design and suitable for 3-6 years old children, the circumference is about 22-26 inches, you can adjust loose or tight by gasing. It is weighing up to 120 pounds. Non-toxic environmental protection of PVC material,thickening made to long time use. We suggestion gasing 70% air when using it,no need 100% gasing. If want to store away, just outgoing gas and fold up, it like a book when fold up ,easy to carry. Temperature is low in winter,PVC material easy become hard and crisp,Please put it in warm water about 15 minites before gasing air.Otherwise it is easy to cracking