This doorbell is an easy install. Drill a small hole through the wall. Place the outside part of the doorbell there and then place the main part of the doorbell inside and install with two screws . It is ready to go. The inside has an old fashioned look. The bell makes a pleasant sound. I have not cleaned the brass. Some people want it to look weathered and some don't. The part that goes inside measures about 4.5 inches in diameter.