The Contraplex is a fine impact mill with two driven pin discs. In counter-rotating mode, much higher relative speeds are possible than with the UPZ fine impact mill, which has only one driven pin disc. The highest relative speed develops at the outermost pin rows and can be up to 250 m/s. The feed material should be brittle with a maximum Mohs' hardness of 3. The fineness can be adjusted by altering the pin disc speeds. The centrifugal forces acting on both discs ensure that even moist, greasy, and sticky products can be processed. The design with the wide-chamber housing is idea for processing these kinds of products. The feed material is often embrittled by intensive mixing with liquid nitrogen.