Volumetric dosing units of the PRK series are designed for manual filling the containers of the capacity between 3 ml and 1000 ml with low-viscosity liquids, i.e. chemical and technical liquids, which do not contain abrasive materials. Volumetric PRK may be utilized for packing into small containers of paints, varnishes, solvents, correction fluids, inks, adhesives, PVA, shampoos, creams, etc.