Double cap valve and adjustable height: pump only the lower chamber for 1-stage height, only the upper chamber for 2-stage height or both chambers for full height. Special valve for easier inflation. .NO AIR PUMP NEEDED: We have tested. Inflating with mouth is faster than using a manual pump, and it saves the hassle of bringing a pump and making noise during flight. .ATTENTION: Emirates, KoreanAirways, Egypt Air and Qantas do not allow this product on your flight. Other airlines please contact the staff. .Must have airplane travel accessories for parents: fill the gap between two seats with this travel pillow to extend the seat length. The extra surface allows children to lie flat or lift their leg to sleep better, or to be a platform where children can play toys and relax. .