The General Hydroponics GH4720 WaterFarm 8-Pack controller/reservoir system automatically maintains proper fluid level in multiple growing units. It consists of eight (8) WaterFarm module units connected to one controller - an integrated 13-gallon reservoir and an 8-gallon controller unit. Users can arrange the WaterFarm units in a design that is suitable for any growing environment, whether it is packing them tight or spacing out the units. This complete system includes: eight (8) WaterFarm modules, one (1) 8-gallon controller, one (1) 13-gallon reservoir, two (2) 10 ft. sections of 1/2-inch blue vinyl tubing, seven (7) barbed 1/2-inch tees, two (2) elbow fittings, two (2) straight fittings, one (1) drain valve, and one (1) clip. For easy, low-maintenance growing, choose the General Hydroponics GH4720 WaterFarm controller system!