GPI 3/4" Automatic Shutoff Nozzle - GPI 906006-83 DEF Stainless Steel Automatic Leaded Nozzle has Viton seals and a 3/4" NPT thread with a swivel and a straight spout. It is specifically designed to transfer diesel exhaust fluid (Urea) fuels. Mechanical Flo-Stop device shuts off nozzle if it should fall from the tank or raises above the horizontal.