The PowerGrower Eco Module incorporates a hexagonal design that enables you to pack many Power Grower Eco Modules together with close spacing for large installations. The PowerGrower Eco will grow small, medium, and large plants up to tomato, cucumber and pepper size. The GH4831 is for use with General Hydroponics Controller systems for multi-unit systems. It is 15 inches across the top and 15 inches tall and consists of a single 3 gallon growing chamber at the top with an integrated 5.7 gallon reservoir below. In addition, it includes a Farm Kit with drip ring, pumping column and related components. It does not include air pump, clay pebbles and Flora Kit. For a complete standalone system, please order a GH4830.