Penn-Plax presents the impressively quiet line of Air-Tech Aquarium Air Pumps. The AT2K2 model quietly aerates and oxygenates fish tanks up to 20 gallons in size. It comes equipped with a single outlet that accepts standard 3/16” airline tubing. It also provides constant air flow and is safe for both freshwater and saltwater fish tanks. Shop Penn-Plax for All Your Pet’s Needs: Penn-Plax is a manufacturer and distributor of top quality pet supplies who specialize in creating excellent pet products for animals both great and small.