Features: Used as oxygen-producing device for fish tank and aquarium, especially use for emergency time. Using high-tech special internal muffler design, really ultra silent air pump. Built-in rechargeable lithium battery, USB interfacecan be charged directly. Come with a metal clip convenient to attach on fish tank. The air stone, diffusing air into the tank, providing oxygen for fish to breathe. 4 Anti-skid fulcrum design, keep balance ensure stable performance. This high efficient aquarium air pump with 1 air stones, 1 silicone tube. Charging port with protective plug, preventing water and dust filling in. This oxygen pump allows for max flow up to 3.5L/min, great for small and medium fish tanks and fits all kinds of aquarium creatures.