I. Usages and features It is mainly suitable for the heat aging test with natural ventilation on wires, cables, plastics, rubber and other industries. In addition, it can also be used in labs of industrial and mining enterprises, research institutes, universities and colleges for baking and high-temperature tests.       LH-401B type thermal extension test chamber is jointly designed and manufactured by Shanghai Cable Research Institute and the Company, which adopts microcomputer control, and its intelligent temperature detector, structure and meters provided as well as materials are designed after the detailed study of airflow and temperature inside the chamber. In practical use, it is characterized by sensitive temperature control, good temperature uniformity, large effective space, stable performance and easy use and maintenance, etc. In addition, its performance is in line with the requirements for heat aging test on wires and cables given in IEC standard and the national standard newly promulgated.