These water circulators from Hailea are used as well as an air pump for maintaining high water quality in a hydroponic reservoir. The amount of through water can be manually adjusted with the flow regulator. Comes with 2 adjustable elbows to direct water flow. Can be used with or without an airline. To use with airline merely connect airline to the 4mm spur. With suction cups for extra support and supplied with 13amp plug.