a system for introducing a predetermined amount of particulate matter to a continuous flowing stream of material . the system consists of a hopper connected via a tube having a screw drive positioned therein to a flowing stream of plastic material to be injection molded or extruded . the hopper and tube are constructed and arranged so that dye material in the hopper contacts only the hopper and the inside of the tube , thereby facilitating easy changing of the hopper and tube to permit the introduction of a different colored dye to the plastic material to be injection molded or extruded . the motor mechanism used to drive the screw can be swung out of the way to permit motors to be changed and also to permit the easy changing of both the hopper and the tube containing the screw drive .