This comprises oils that make up the distillation residue. It comprises all residual fuel oils, including those obtained by blending.

Its kinematic viscosity is above 10 cSt at 80 degrees C. The flash point is always above 50 degrees C and the density is always more than 0.90 kg/l. Sulphur is less than 0.5% which applies to refineries and power plants, which is very environment friendly. It also Comes from Russian origins.