The HEYI piezo aquarium air pump is a small aerator pump without mechanical drive. Unlike conventional electromagnetic air pumps, this pump is only driven by a thin piezoelectric ceramic plate. There is no motor, no diaphragm and no other mechanical parts. The air flow is generated by the piezoelectric ceramic. The piezo-ceramic starts to vibrate when an electrical voltage is applied. This not only makes the HEYI piezo aquarium air pump extremely quiet and durable, it also saves a lot of energy. The power of the small air pump is sufficient to operate two air diffusers with which the aquarium can be aerated.HEYI Piezo-Aquarium Air Pump+ no motor, driven by piezoelectric ceramic plate+ whisper quiet, super compact and light+ two separate outlets+ no electromagnetic interference+ energy saving and long lifetime technical data HEYI Piezo-Aquarium Air Pumppower: 2x 13 l/hPower consumption: 220-240V/50 Hz, 1.5 WPressure: 12 kPaNoise level Delivery includes power supply unit, 2x air stone, 2