Ruggedness and waterproof design: We give priority to speakers that are built to survive the knocks and bumps of travel. We favor speakers with an Ingress Defense (IP) rating, which tells you exactly how dustproof and waterproof a speaker is. Most airlines allow you to bring a speaker on https://www.bluetoothspeaker.top/waterproof-subwoofer-portable-outdoor-bluetooth-speaker-smart-wireless-speaker/