Twin outlets with auto charging design. As power failure, it can last to work uninterruptedly. Double vents, three-section adjustable design. In regular use, there are weak/strong and stop functions for choice. As power failure, there are continued and intermittent pumping modes for your option. As using intermittent pumping mode, it allows non-stop pumping up to 20 hours. Shock-absorbing device inside. Strong pumping power, quiet(<45 dB) and low vibration. It adopts high quality materials for prolonged service life. It uses rechargeable battery that needs no water replenishment in case of blackout. Additional with overcharging protection electronic circuit design to prolong battery life. This product can increase dissolved oxygen and remove harmful matter in water. With on/off switch control. 2x4L/min, 12w