A manhole (alternatively utility hole, maintenance hole or access chamber) is the top opening to an unerground utility vault used to house an access point for making connections or performing maintenance on underground and buried public utility and other services including sewers, telephone, electricity, storm drains and gas. It is protected by a manhole cover, a (usually metal) plug designed to prevent accidental or unauthorized access to the manhole. Manholes are usually outfitted with metal or polypropylene steps installed in the inner side of the wall to allow easy descent into the manhole.