A CPU detects a temperature of a central part of a heating roller. Each component includes a flat plate having opposing surfaces which are joined together by a snap-lock device. A first surface electrode is positioned on the first surface of the semiconductor chip and coupled to a first end of the first through electrode. The side edges of each panel are slightly curved to maintain the properties and proper appearance of the insulator. The compression section also includes a cylinder head secured to the rib for covering the open end of the cylinder. Particularly, the embodiments described herein enable two or more playback devices to be paired, such that multi-channel audio is achieved.