"The advanced sound-reducing technology in TetraTec APS air pumps means that reduced noise levels do not come at the expense of a more powerful air production system. Suitable for tropical, marine, goldfish and reptile aquariums. These extremely quiet and powerful air pumps increase oxygen levels running air driven ornaments and operating under gravel filters. The Tetra APS air pumps are made in conjunction with leading sound engineers and provide high flow rates of air even in deeper aquariums. The modern design and state-of-the-art technology of TetraTec air pumps come with adjustable airflow CE certified TUVGS tested safety and reliability assured by a 3 year guarantee. The APS 300 (for aquaria up to 60”) has twin outlet."