Choose this SRS-600 12V ProPack Rechargeable Backpack Sprayer from SHURflo. This model, which features a 4-gallon capacity tank, is unmatched in performance, comfort and convenience. It contains a built-in mechanism that maintains a constant spray pattern, which eliminates the need for the wearer to pump up the sprayer. Select from four different pump speeds as well as an adjustable cone nozzle for unlimited versatility in outdoor spraying applications.