Extruded plastic sheet is heated and formed over a mold to create a contoured tray that cradles and protects each specific part. This process allows nesting of parts and increases part density. In addition, tray cavities form to carry multiple variations of the same part. Trays can stack or nest during shipping and storage. Plus, all SSI SCHAEFER trays are recyclable. Common materials are high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS), polyvinyl chloride (PVC), and polypropylene (PP).