Description: Plastic air valves are for fish tank aquarium use. Help to increase oxygen and keep air fresh, create healthy environment for your fish. Easy to connect hose, outlet and inlet hose diameter in tahe same size. Two way plastic valve can be used as an in-line valve to control air flow from pump. Available Size: 8pcs, 10pcs, 12pcs, 14pcs, 16pcs, 18pcs, 20pcs, 22pcs, 24pcs, 26pcs, 28pcs.