Bluebird Box House Equipment Grip 'N Grab 19302306 Grip 'N Grab Fatty acids for a full Made with insect and rot resistant premium cedarAir vents allow for maximum air ventilation through wall and floor openingsClean out doors provides easy access for cleaning and bird viewingElevated mesh floor aids in management of blowfly Durable rust free galvanized wire meshPredator guard extends entrance hole to protect against predatorsPredator guard entry hole has a diameter of 1 1 2" Predator guard with an entry hole 1 9 16" in diameter for Western bluebirds can be purchased separately on the Replacement Parts page and retrofit to the bluebird houseBluebird house body has an entry hole with a diameter of 1 9 16" to allow it to be used for both types of bluebirdsFledgling kerfs provide extra grip for fledglings to climb out