1、Made of high quality PVC material, sturdy, durable and long service life. 2、When the position of the air pump is lower than the surface of the water, to prevent water backflow damage to the front end of the air pump or other product equipment, after the addition of stop valve air pump can be higher than the surface of the water or lower than the surface of the water placed. 3、There is no danger of water backflow when the air pump is cut off and stopped working, it is the small guard of the gas supply facility. 4、Using air pump is very easy to handle and use to prevent water from entering the machine pump. 5、Used as an oxygenation pump due to the pressure difference between the interior and outside when it suddenly stops working, which causes the water flow to reverse, damage the oxygenation pump and cause the water in the cylinder to overflow to form a property loss. Prevent the water in the fish tank from flowing back into the air pump, burn the air pump to avoid danger, it is an indispensable accessory of the air pump.