The water pumps operates with low noise and is very quiet, without causing any interference to the surrounding environment Simple wiring design: The black square is the wiring terminal, which can be easily disassembled not needed Pay attention to the wire connection, with the black wire being the negatives electrode, to ensuring safe and correct operate and avoid the risk of short circuit Not only can it be used as a water pumps, but it can also be used as a small air pumps to meet your different needs The M20 water pumps is compact in size and in various models Supports 5V power supply, easily powered by 3-4 1.5V batteries ( Not included, Manufacturer: Hsyzygian