Castaldo® Mold Lock Formers are a convenient way to make mold registration locks without cutting. They are designed for making molds using the fast, easy powder separation technique. Castaldo® Mold Lock Formers are stamped brass pieces with prongs that can be inserted into the rubber before vulcanization. They may be used with any of the following Castaldo Jewelry Molding Rubbers: White Label®, Gold Label®, No Shrink Pink® or Castaldo Super High Strength™ Silicone Jewelry Molding Rubber or Econosil® Jewelry Molding Rubber. Castaldo® Mold Lock Formers are packaged in plastic bags containing approximately 155 pieces, weighing approximately 3 ounces / 70 grams. Instructions.