The Under Current® is the world’s first recirculating Water Culture Hydroponic System featuring our Patented Sub-Current Culture® Method. This innovative application circulates literally hundreds of gallons of solution per hour beneath plant roots. The Under Current® supercharges the solution with dissolved oxygen, creating a hyper aerobic condition. All Current Culture Systems now come with white ABS lids. These new white lids are made of durable ABS plastic, are UV stable, 100% non-translucent and highly reflective. New side-entry air ports on all Current Culture Under Current® systems now include an innovative side-entry for the air diffuser lines utilizing a uni-seal for each module. This allows you to remove the entire module lid without disconnecting the air lines, making root-zone inspection much easier. Includes: 13 gallon multi mod growth modules with drain well, 30 in center 5.5 in heavy-duty white lids with porthole, 5.5 in heavy-duty net pots, easy clean manifolds with UC spin-tight bulkheads, add-back kit, high flow aeration manifold, air pump bank with air flow regulator, premium linear air pump(s), Danner Mag-Drive return pump with 1 in return hose, adjustable float valve with reservoir adapter kit, optional drain out kit available and Cultured Solutions XS Growers Pack. 4 site has a 3 ft 8 in x 6 ft 8.5 in grow area, 6 site has a 3 ft 8 in x 9 ft 2.5 in grow area, 8 site has a 3 ft 8 in x 11 ft 8.5 in grow area, 12 site has a 3 ft 8 in x 16 ft 8.5 in grow area and 16 site has a 3 ft 8 in x 21 ft 8.5 in grow area. These items are drop ship only.