The FloraFlex? 7.5-12 in Universal Round FloraCap? is a patent-pending revolutionary tool for top feeding that also helps eliminate algae. The FloraCap? is designed to give you a more consistent flow rate, even distribution, increased air flow, and stabilization. Fill the cap with water and nutrients by hand or automate with FloraClips. The FloraCap? strategically covers the top of the media allowing the root zones to dry at a more consistent rate and delivering the necessary oxygen your plants need to thrive. Fits pots from 7.5 to 12 in diameter.