The FloraFlex? Matrix Circulator is part of the Matrix System, a patent pending first of its kind Top Feeding Wicking System that provides the most even way to deliver water and nutrients to your plants. It can be used with pots ranging from 7.5-18 in diameters. You will need a Matrix unit, same size Matrix Pad, and the correlating Matrix Circulator. Water and nutrients travel into the Circulator, hit the slope of the Matrix and are pushed outward into eight maze sections that have individual holes dripping the water and nutrients onto the Wicking Pad. The Circulator has two barbed nozzles to attach 1/4 in OD FloraTubing that allows you to automate the Matrix System. Use the 2-1/4 in Circulator with the 7.5 and 9 in Matrix. Use the 3 in Circulator with the 10.5, 12.5, and 15.5 in Matrix. Place the Matrix Pad on the surface of your plant, the Matrix Unit on top of it, press down, fit the Circulator into the center holes, and connect your 1/4 in OD tubing to the Circulator.