The Scott's professional is the only backpack sprayer you need . Doing the work of both piston and diaphragm pumps, this 2-in-1 system boasts an internal piston pump, delivering high pressure spraying and the internal agitation paddles enhance performance when spraying wettable powders. The No Leak internal pump and pressure chamber allows pressures to reach 150 PSI, all while keeping the liquid in the tank and not running down your back. For extra comfort, the Scotts Professional Backpack Sprayer has thick, adjustable padded straps, waist belt, chest strap and harness with lumbar support. Tested to over 1,000,000 cycles with wettable powder without failure and backed by a 5 year warranty, the Scotts Professional Backpack Sprayer is sure to stand up to daily professional use, working as long and hard as you do.