An air vent FK-12 Opening sidewall grille made of aluminum alloy air spray made, FK-12 may open side wall grille air shutter form the entire air show, switch freely between the shutter and frame conducive to installation and supporting the use of the filter, commonly used in room air return. And this outlet supporting FK-5 filter is fixed on the shutter, so as long as the shutter flick on both sides of the bolt by hand, the shutter can be opened, will be able to extract or insert the filter from the valve: closed, as long as the shutter onto both sides of the spring bolt lock automatically, like a smooth appearance.