The Milwaukee 4-Gallon Sprayer Tank Assembly with SWITCH TANK? is an interchangeable tank powered by the M18? Powered Base with SWITCH TANK? (not included). The sprayer tank assembly includes the pump, hose and wand. The design allows you to add on tank assemblies for different applications, eliminating cross-chemical contamination. The 4-Gallon Sprayer Tank Assembly features a dual diaphragm pump for longer pump life and Viton? seals for increased durability against harsh chemicals. The sprayer tank also has a wide mouth opening for easier pouring and a strainer that filters debris from getting into the tank.