Jacketed Hose Assemblies are generally used to heat fluids, which are normally viscous at 70°F. Assemblies use the jacketed section to carry steam or hot oil, to raise the temperature of the fluid moved in the internal hose, thereby lowering the viscosity and permitting uninterrupted material flow. Jacketed hose assemblies are made up of two flexible hose units, one inside another. Reference Corrugated Metal Hose. Alloys include bronze, steel, stainless steel, and Monel. Working pressures are per application. Temperatures up to 1500°F. A variety of size, length and end fitting configurations are available.