Over Molding is a colorful solution for too complicated part. It's kind of combination of inserts and final molded component. Pre-mold is first insert molded. Then a second tool is used to incorporate the pre-mold as an insert to be over-molded to form the final molded part. Over molding including TWO set molds to finish a complex plastic component. Normally use rigid plastic with soft resin as bumper function, such as bumper use TPE/TPR work with ABS, PA 6, PC, PBT and so on