One aspect of the invention relates to a brown pigment composition with excellent weathering resistance containing iron oxide, chromium oxide, and one or more alumina andor silica components. This heat treatment unit is improved from the conventional one in that it can give desired mechanical properties which are required by each part of metallic work requires without increasing the investment cost. A capacity of the network is probed at the first device for the sending and receiving the communication. Drivers are provided for driving the door to open and close.