This double-chambered bat box is made to house around three dozen bats. They are based on a structural design scientifically-proven to work for the most common smaller bat species, including the Little Brown Bat. The gap in the front is for air flow. The bats land on the landing pad at the bottom of the box and enter from below. All surfaces inside the box are textured to allow the bats to move easily throughout the box. Comes with hanging hardware and necessary screws. Box is approximately 31" tall, 15" wide, and 4" deep.