Dundas Jafine DRB4XZW Recessed Dryer Vent Box, 4", White Allows the dryer to be pushed up against the wall instead of having to be positioned 5 - 6 inch away in order to accommodate the dryer duct The box also completely protects the duct from being crushed and lint build-up is minimized due to the limited kinks and bends Made of high impact polystyrene (ul94hb rated) Built-in draft blocker helps reduce cold air backdraft into the home Oval to round duct adapter threads on easily to the duct for a quick installation