Solo 475-Deluxe 4-Gallon Professional Diaphragm Backpack Sprayer  (Older Model) High-performance diaphragm pump for use with wettable powders and liquid formulations Durable, professional grade, brass adjustable nozzle Pressure gauge for better control of spray pressure Adjustable pressure regulator with four positions: 15, 30, 45, 60 psi Fold-away handle with wand retainers for easy storage