The Aqua Life Deluxe Air+Check Valve allows you to operate up to four (depending on a model selected) air-powered accessories or devices using a single air pump. It features a built-in anti-siphon check valve that protects your air pump against water damage, and allows you to independently regulate the air output for each connected accessory. A convenient hang-on design fits most standard aquariums, and an integrated air filter supplies clean air to your aquarium. Perfect for accurate and adjustable control of air stones and diffusers, aerating ornaments, and more! Available in 2, 3 and 4-outlet sets.