Control the flow while dispensing diesel fuel. Nozzles are aluminum, which is lightweight with good corrosion resistance.Nozzles with automatic shut-off will stop dispensing when the tank is full or if the nozzle falls from the tank. They have a built-in check valve that reduces spillage when withdrawing the nozzle from tank. Nozzles have an angled design, which reduces hose kinking for efficient fueling. They come with a plastic scuff guard to protect the nozzle from damage.Nozzles with manual shut-off have a trigger to stop the flow. Do not leave the nozzle unattended when in use.Styles B and C are also known as truck-stop nozzles. They have higher flow rates than Style A to dispense large quantities of fuel quickly.