Diving breathing tube is a kind of equipment that can make snorkelers stay in the water and still breathe. The general design of breathing tube is an elbow with one end open and the other end biting. The inner diameter of the breathing tube is about 2 cm and the length is about 30 cm. The longer the breathing tube, the better. When the length of the catheter exceeds 40 cm, the lungs can't effectively inhale against the water pressure, and carbon dioxide will stay in the catheter when exhaling, which will reduce the ventilation efficiency and may cause hypercapnia.
Diving breathing tube can be divided into silicone breathing tube and pvc breathing tube according to the material of bite and snake belly tube.
According to the design structure, it can be divided into full wet type, semi-wet type and full dry type. The difference lies in whether there is a buoyancy closing valve or a wave-proof structure at the top of the breathing tube.