This Ultimate Bluebird House has  a side door engraved with "Clean" and the other side with "View".  Behind the VIEW door is a clear plexy glass so the nest willnot be disturbed while you view.  They also have a raised screen floor to reduce blowfly infestations.  There are also predator guards and an extended roof.  The CLEAN door opens for easy cleaning of this house.  Made of 7/8" Natural Cedar, it has a 1.5" hold with a copper portal.  Overall dimensions 7" L x 8.75" W x 15" H.