This Solo 4 Gallon Backpack Sprayer is designed with a diaphragm that is made of top quality Villon material which makes it resistant to harsh chemicals and prolongs life expectancy. It is capable of producing up to 60 psi. Can be used with disinfectants, fungicides, herbicides, insecticides and fertilizers. Features a carrying handle for easy transport and deluxe padded strap and waist belt. The HDPE tank has a large 4.25" opening.