This house holds up to 100 bats! The house is made out of cedar with a one piece plywood back to eliminate heat lose through cracks. The house is fully caulked and screw constructed. Made to The Organization For Bat Conservation Specifications. Insect-eating bats are supremely good at what they do: a single little brown bat can catch and eat 600 mosquitos in an hour. Thus bats play an important role in regulating insect populations; in those places where bat populations have been severely reduced by human activity the numbers of fruit flies and other pests have risen dramatically. Measures 24 x 14 .25 x 3.