The versatile 12-site Ebb & Gro System allows different size and shape configurations to fit gardeners exact growing needs. For easy set-up, the interchangeable two-gallon grow pots connect to the controller unit and the controller unit connects to the 55-gallon reservoir. Ebb and flow system floods and drains planters several times a day. System includes necessary tubing and pumps, features a built-in timer, and all components fit into the reservoir for convenient transportation and storage. Optional six-site Ebb & Gro expansion kit also available.This System Can handle up to 48 total plant sites!!