The Heartwood Eastern Bluebird Joy Box has a clean and simple design with hole opening and interior sizing specific for the Eastern Bluebird. The slanted roof provides a generous overhang, to protect the 1_1/2" diameter entrance hole from the elements. At the top of the frame ventilation holes are provided to help regulate interior temperature, and slots at the bottom provide drainage to keep everyone warm and dry. Maintainence is a breeze with the easy twist latch and sliding front panel that inverts in order to make it a winter roost when the temperature drops. Rugged construction features 13/16" solid cypress and stainless steel nails. Mounts easily to a post or tree using the two predrilled holes on the back of the house. Made in the USA. Opening: 1_1/2" dia. Dimensions: 10"L x 6_1/2"W x 17"H Shipping Weight: 10 lbs