Constructed of Eastern White Cedar, harvested and milled in Maine. Front panel opens for easy cleaning. Etched surface on inner panel allows fledglings to climb easily out of the box. Ventilated, with drainage openings in the bottom. 1.5" entrance hole is equipped with wood predator guard to keep mammals from accessing the box. 1.5" Predator Guard is recommended to prevent chewing by squirrels. Woody's.