The Pro Series Wide Mouth Backpack Sprayer has a four-position pressure-control valve that helps you determine droplet size and spray drift. Pressure settings for 30, 45, 60 and 80 psi. 6"-dia. tank opening makes mixing contents easier. Three-stage filtration system includes a strainer basket, filter in the tank inlet to the piston cylinder and filter in the shut-off assembly. Pump handle for the 4-gal. tank attaches to either side. Viton® seals.