ANS Silicon Air Tube is a flexible, hollow hose made from materials like silicone or PVC, used to transport air from an air pump into the aquarium. It connects the pump to various devices such as air stones, bubble walls, or filters. The air introduced into the tank helps oxygenate the water, providing better conditions for fish and plants. It also aids in water circulation, which is crucial for keeping the tank environment healthy and preventing stagnation.