Our M18™ SWITCH TANK™ 4 gal backpack sprayer delivers the industry's first interchangeable tank design with no manual pumping. Designed to meet the needs of professional landscape maintenance, the battery powered backpack sprayer provides you with instant, constant and adjustable pressure up to 120 psi and a 25 ft spray distance. The 5-mode pressure adjustment knob adjusts the pressure between 20 to 120 psi, giving you the capability to complete a wide range of applications. Our M18™ REDLITHIUM™ XC3 Battery (sold separately) provides you with up to 12 tanks of spraying per charge. The 4 gal sprayer tank assembly features a dual diaphragm pump for longer pump life and FKM seals for increased durability against harsh chemicals. The sprayer tank has a wide mouth opening for easier pouring and a strainer that filters debris from getting into the tank. The backpack frame includes wide straps giving you added comfort during extended spraying applications and a handle for convenient transport and storage. The 4 gal sprayer is made up of two components the M18™ SWITCH TANK™ powered base and the SWITCH TANK™ 4 gal sprayer tank assembly. The powered base includes the motor, battery compartment and REDLinK™ electronics, while the interchangeable tank assembly includes the pump, hose and wand. The isolated pump, hose and wand design allows you to add on tank assemblies for different spraying applications, eliminating cross-chemical contamination. It also provides you with the ability to replace the tank assembly at a lower cost of ownership compared to replacing the entire sprayer. The powered base is also compatible with the SWITCH TANK™ 4 gal concrete sprayer (49-16-28CS) and 4 gal water supply (49-16-28WS) tank assemblies. Our M18™ SWITCH TANK™ 4 gal backpack sprayer is part of the M18™ system which is fully compatible with over 175 tools.