The M18™ 4-Gallon Backpack Sprayer w/ SWITCHTANK™ delivers the industry's best pressure control, with no manual pumping and an interchange tank design. The sprayer's instant, constant, and adjustable pressure enables ultimate spraying control across a wide range of applications all with no manual pumping required for reduced fatigue. The interchangeable tank design allows you to add on tank assemblies for different spraying applications, eliminating cross-chemical contamination.