Hygger HG-811 Quiet Air Pump stands out in small fish tank pumps for its light-weight, quiet and energy saving. Build in a thin piezoelectric ceramic plate, unlike traditional air pump, it is effectively reducing the noise when its working. It is less noisy than many other pumps in the market. It is suitable for aquariums with volumes up to 15 gallons.Specifications: Power: 1.5W Max Flow Rate: 420ML/Min Voltage: 110~120V 50-60Hz Noise: <35dB Pressure: 12KPa Air Tube: 4mm (0.16inch) Dimension: 2.4 x 2.4 x 0.8 inDirection: 1. Soak air stone for about 1-2 hours before use. 1. Connect air stone to air tube. 2. Connect air tube to air pump outlet. 3. Attach air pump onto outside wall of aquarium tank, but locate the pump above water level to avoid any possible water counter flow. 4. Immerse air stone into aquarium tank. 5. Connect power adapter to electricity socket, then go.Warm Tips: ? 1. The pump is NOT SUBMERSIBLE, please do not put it into aquarium. Keep it dry. 2. If air pump immerse into water accidentally, please shut off power supply immediately. 3. For your safety, if have any damage of power cord or air pump, you should stop use it immediately. 4. To get the maximum air flow and extend air pump service life, we suggest to clean airline tubing and airstone regularly. 5. Must to cut off the power of air pump before put your hand into aquarium. 6. Place air pump above the water level of aquarium. If not, install a check valve in case backflow and burn the pump. HG-811 Fish Tank Air Pump comes with all air pump accesories - air stone, the pump, and a 3.6 ft silicone tube, providing nice bang for your buck. Attention: usmagob is the only one seller of selling hygger mini air pump. Other stores do not authorize to selling hygger mini air pump. Please choose us when add to cart. Thanks.