These are custom built in my shop by myself and sometimes my daughter. Built out of cedar boards. They will fit up to a 14” diameter tree. Any bigger size tree will need to add more chain to the birdhouse to reach around the tree. They have a hinged door on one side to allow for easy cleaning each year. The legs fold up to allow for easier shipping. When you receive the birdhouse, you will have to fold the legs back down and replace the two screws in the predrilled holes.(screws included)