Note: The Merry Muscles includes 1 hook in the package. You may purchase extra screw-in hooks to install in different areas of your home. Install into a ceiling beam/stud, or door frame. If installed in a door frame, you can still close the door when the exerciser is not in use (as shown in the fourth picture). You may remove the hook once baby has outgrown the Merry Muscles, and fill the small hole with wood putty.