Converts from a nest box to a winter roost by removing two screws and inverting the front wall; then insert three included dowels for perches. When configured as a winter roost with the front wall's entrance hole near the floor, the front wall fits tight against the roof to more efficiently contain the warmth which rises from the roosting birds. When configured as a nest with the front wall's entrance hole near the roof, there's a space between the wall and the roof to provide ventilation. The front wall tilts open for inspection and clean-out and is held closed by an L hook. A slate guard discourages squirrels. Made from eastern white pine for insulation and durability. Dimensions: 7" W x 12-1/2" H x 8-3/4" D. By Coveside Conservation Products.