This EcoValve pressure regulator limits the pressure of your spray wand to 44 pounds per square inch (psi). Installation is easy. Simply screw onto the end of the spray wand just before the nozzle. The EcoValve limits the spray pressure of your wand, no matter how much you pressurize the pump chamber. Use this pressure regulator to reduce off-target sprays and over-spraying. It also improves the ability to properly calibrate your sprayer. Use this regulator when working with fungicides and pesticides. Fits all Jacto backpack sprayers!