【3 in 1 Function】: ① Dirt Suction. Gravel Vacuum for Aquarium equipped with a duckbill suction inlet accessory, and it is easy to suck the feces away. ② Sand Washing. Aquarium siphon with 3D Filter Basket Net, protect your love fish and small gravel from suck out of the aquarium. ③ Water Changing. Built-in dual airbags, atmospheric cavity, good resilience, effortless operation. 【Working Principle】: hygger's unique patented design --- equipped with a handle type manual press, which has more operating space and saves labor and brings convenience, by testing the fastest speed is to press 7 times. Sand Washer has 2 thickened airbags inside, which can pump water quickly. And using PP ABS materials, resistance to extrusion, do not worry about airbag damage and leakage, can be used for a long time. 【Easy to Use】: Push the siphon switch of the aquarium siphon vacuum cleaner several times, and make sure that the inlet tube part is full of water, and then observe the outlet hose. After the water continuously flows out, you can stop push and observe whether it will automatically. If not, continue to operate until the water will flow out quickly and automatically. The sand can move up and down in the extension tube to remove debris from your aquarium.