"This Hudson Bak-Pak duster sprayer is powered by a gas engine to disperse granular fertilizers and pest control products. Dimensions L x W x H in. 20 x 12 x 28, Pump Type Duster, Tank Size gal. 3 3/4. Portable, flexible, high-efficiency backpack duster 2.4 HP engine 3 3/4-gallon tank Quick adjustable padded shoulder straps and backrest for operator comfort Easily changes from duster to mist blower with two interchangeable tank inserts"