4) Gallons Chauvet DJ HDF High Density Fog/Smoke Juice Fluid Hurricane Machine Gallon of Chauvet HDF High Density Fog Juice Fluid is Formulated specifically for use in all water-based haze & fog machines Can be combined with other Chauvet products Produces thicker and denser smoke than original HJU Doesn't stain or leave residue and is Non-toxic, non-flammable & unscented FDA compliant