Accepts all types of 4' flex duct The damper mechanism can easily be opened and closed and may be completely removed for full flow Grill rotates a full 360 degrees to direct air flow where desired 4' diameter mounting collar; overall 5' diameter, 2.75' depth Color: Black RV Designer H815 Provent Dampened Vent - Black SKU: 1023.4335 UPC: 601320488150