Pen Plax AT2K1 Air-Tech Aquarium Pumps DESIGNED FOR QUIET OPERATION: with rubber armature, silicone polymer flappers, a thick cover, and raised rubber feet, this air pump is of the quietest on the market SINGLE AIR OUTLET: this air pump accepts standard 3/16 airline tubing, and is ideal for tanks up to 10 gallons large RELIABLE AND DURABLE: Penn Plax has designed this pump with reliability and durability in mind  this pump will last you years  at an affordable price and quiet operation COMPATIBLE WITH ALL AQUARIUMS: safe for freshwater, marine, and reef aquariums. Whatever your aeration needs; the Air Tech pump has you covered