 ring layers; 'open' which has a cutout for the USB connector, and 'closed' which has no cutouts.  You can choose how many of each layer is suitable for your case.<br />
                        This case type will actually produce the CAD files for <b>all</b> the layers of the sandwich case.  You will be able to choose how many of each layer you want cut and build the case completely from the output of this tool.</li>
                      </ul>
                    </div>
                  </li>
           