A stiffness mechanism for a boot having a shell with a flexibility slot and a cuff pivotally secured to the shell includes a buckle assembly selectively engageable with a portion of the shell for selectively securing the cuff to the shell. The signal line is a signal line that transmits data unidirectionally to the second MAC layer circuit from the first MAC layer circuit, and a signal line for transmitting data from the second MAC layer circuit to the first MAC layer circuit is opened or is connected to a ground. The acoustic absorber layer is positioned on a passenger compartment facing side of the vehicle component. A desired splitting ratio may be achieved by adjusting the angle between the input waveguide and the MMI portion. The tip portion of the upper magnetic core rear portion is overlapped and connected to the upper magnetic core front portion on the medium-facing surface side of the apex, extending therefrom to the upper part of a coil and a coil insulating layer.