Birchmeier Flox Valve Assembly is a replacement for Birchmeier Flox 10 Backpack Sprayer, Birchmeier Iris 15 Backpack Sprayer, Birchmeier Senior 20 Backpack Sprayer, and Birchmeier BCS Closes System Backpack Sprayer. It helps in regulating the flow of water and prevents the pressure from increasing and building up. It includes O-rings.