Why run one mold in a press when you can run two. Stack mold technology essentially runs two single face molds back to back with the injection system in the middle. A sprue bar runs through one half of the mold to deliver the material to the injection system and a centering device opens the two parting lines at the correct rate. Different style presses and injection systems all have their slight differences in accomplishing this task. Pelco has already gone through the learning curve to help educate the end user on what will be required and how these systems run.