A device is described for accurately transferring multiple individual fluids from multiple source containers into a single receiving container. Fluid flows from the multiple source containers through individual fluid conduits to a chamber having a single fluid outlet conduit. The fluid outlet conduit is in fluid communication with a single receiving container. A pressure conduit is in communication with the chamber for alternately creating positive and negative pressures in the chamber to cause fluid to flow from the individual source containers into the chamber, and to cause fluid flow from the chamber into the receiving container in response to commands from a controller.