The Aquatic Life Float Valve Kit allows you to fill large tanks, containers, and aquariums automatically. If you are using this with a reverse osmosis or RO/DI system, you WILL NOT need any other components, as this kit includes the necessary auto shut-off valve, check valve and tubing. The adjustable float connects to standard 1/8" MPT - Connects Directly to Faucet - Includes check valve. Minimum Operating Pressure: 40 PSI - Maximum Operating Pressure: 80 PSI.