11B Automatic Nozzles are designed especially for self-service pre-pay of card-lock system to help prevent gasoline spills. The 11B cannot be opened until the pumping system is pressurized and closes automatically when the pressure is removed. This means the JH-11B is closed when placed back to the dispenser. Accurate flow control allows your customers to top off their tank to the exact amount they want, and it's easy to stop gasoline flow precisely.