Electric Aquarium Gravel Cleaner, Yosoo Aquarium Gravel Cleaners Battery Electric Powered Fish Tank Washer Siphon Vacuum Water Changer Pump Filter (Battery Not included) Aquarium Vacuum Cleaner + Water Siphon(Battery or adaptor not included) Easy to install and use. Supported two suction pipe sizes, suitable for both small and large aquariums Can clean gravel, siphon the fish excreta and other dirt out effectively without requiring a water change. Also be used as a water siphon for water changes, or to empty your aquarium when you connect a hose to outlet Battery powered - 2 x C/LR14 Battery(Not Included),safe for you and your fish. Another power on/off button to control external power supply(DC3.3V transformer not included).The suction power will be bigger if you use DC adaptor and the product service life will be longer if you use battery. Telescopically adjustable height for big and small aquariums. Hose & Filter bag included. Before starting , please confirm the mark "start water line" and "warning water line". When start to work, please flood the water to the "start water line" but do not over WARNING WATER LINE. If the suction decreased, please try to turn off the power supply and open the product to check whether blocked.