According to the invention a device for precise metering of a fluid volumetric flow of low flow rates down to zero volumetric flow of a liquid component in a mixer feed line for mixing plastics is provided, the device having a fluid supply tank that is in fluid line communication with the mixer feed line via a pump and through a volumetric flow meter, is characterized in that a fluid return line, which leads back into the tank through a second volumetric flow meter and which branches off from one of the fluid lines between the tank and the mixer feed line downstream of the first volumetric flow meter through a distributor apparatus that has one input and two outputs, namely one into the return line and one into the mixer feed line, and that distributes an input volumetric flow into the two outputs, and specifically in an adjustable fluid rate ratio.