If you're using your ozone generator with any type of water application, a check valve is key. Simply connect it in the proper direction between two pieces of tubing and water will not be able to continue up the tube. This piece comes free with the O3Elite and O3Arc Ozone Generators. Made with Teflon.
You can order individual check valves by choosing One under Options and then using the quantity box. Choosing 5 or 10 Packs makes it easy to save on shipping costs for expedited or international orders.