We purchased one of these previously with a door and top.  We use it indoors to keep puppy in and cats out.  It worked so well for us that we purchased two more without doors for the backyard. We have a teacup poodle and although our backyard is fenced we feel much more secure with her in this enclosure.  She is so small that she could squirm under the fence if there was an undected hole. The fence  is shared with a neighbors backyard and two very large dogs so this makes our little one much safer.