Aquarium Battery-Powered Fish Tank Vacuum Gravel Water Filter Cleaner US 8H52 Easy to install and operate. Press the on/off button on the top, the water in aquarium will be pumped out automatically through a hose for changing water. Also can clean gravel, siphon the fish excreta and other dirt out effectively without requiring a water change. The upgrade outlet water head and scraper are convenient to clean the dirt in the corner and on the wall. Powered by two batteries, safe to use. Another power on/off button to control external power supply(not included). With adjustable structure, it is suitable for small and large aquariums.