Cores and tubes are used for mailing, shipping, material handling, and product display. Product types include plastic cores and plastic tubes, paper core and paper tubes, and metal cores and metal tubes. Mill cores, converter cores, carpet tubes, and other specialty products are also available. Cores and tubes are used mainly in continuous processes, such as the production of papers, films and foils. These materials are wound in the form of a roll or web that is supported by a core. Customers can then move, store, and handle these finished materials more easily. Paper cores and tubes differ in terms of type and size. There are many different types of products. Choices for paper tubes may include 2-piece telescopic or 3-piece telescopic, curl and disc, notched cores, slotted cores, medical cores, cosmetic tubes, and labeled tubes. Typically, dimensions are specified in inches (in) or centimeters (cm). Thickness is another important parameter to consider. Like paper tubes, paper cores may be designed to meet a customer’s requirements. Product specifications include inner diameter (ID) and outer diameter (OD), wall thickness, length, and crush strength. Some paper cores and tubes have covers that are made of colored papers, parchment, or foil. Others feature custom printing. Custom packing is commonly available. Plastic cores and tubes may be made of either clear or colored plastic. Clear plastic cores and clear plastic tubes are often used in packaging applications where product visibility is important. Colored plastic cores and tubes may be used in the continuous processing of papers and foils. Typically, both types of plastic products are extruded. When selecting plastic cores and tubes, there are several parameters to consider. These include tube shape, wall thickness, and cap-and-plug options. Most plastic tubes and plastic cores are round or square. Wall styles are designated as think wall, medium wall, or thick wall. In terms of cap-and-plug options, some products are sealed on one or both ends. Suppliers may also provide open-end tubes and cores. Metal cores and tubes are more durable than paper or plastic cores and tubes. Materials of of construction vary, but most are made of continuous metallic strips that are selected for durability and plasticity. Product specifications for metal cores and metal tubes include shape, thickness, and application. Specialty metal cores and tubes are also available.