When the side window is open even slightly, air emitted from the front opening flows upward along the window and re-enters the passenger compartment. However, the MUGEN visor design has such a unique configuration that it prevents the back flow and efficiently uses negative pressure to discharge air from the passenger compartment. Furthermore, wind noise is significantly reduced compared to that generated by many other visor fitments, while at the same time rainwater is prevented from entering the passenger compartment; both factors that provide a substantial improvement in passenger comfort.