3V-7V DC High-power Small Mini Micro Air Motor Pump, can use it Micro Blood Pressure Monitor Oxygen Inflatable Air Pump. This product has stable and reliable performance, Small, hand-held instrument for pump-priming, low noise, low power consumption. Especially suitable for high environmental requirements. excellent quality and long service life. Ideal for provide oxygen for aquarium or other project. This pump may have a little noise, you can consider use a lower voltage, when the voltage is 3 V - 6 V, the air pump still work perfectly, and the sound will be acceptable.