The Rain Bird DV/DVF valve is the premium valve product chosen by more professionals than any other valve on the market. Its long history of reliable performance makes it the natural choice for your landscape. Its consistent, problem-free performance means you can spend less time thinking about your irrigation system and more time enjoying your landscape. Use DV/DVF series valves in locations where the use of a separate pressure vacuum breaker (PVB) or a double-check valve is required by city codes to protect against back flow. Check your local city codes to determine what type of valves are required.