Heavy Duty Kneader is categorized in the closed system mixer same as Dispersion Kneader. It is almost the same as the Dispersion Kneader. However, the only differences are Motor Horsepower, Gear, and the Mixing Blades Size because, in Heavy Duty Kneader, it uses more powerful options. For example, in 55L Heavy Duty Kneader, it uses 75L mixing blades and motor while the chamber is still 55L