An installation body for door and/or window handles is composed of a base body that has at least two passage holes for the insertion of fastening screws and a recess providing a receptacle for a detent ring. The base body is made up of a top side and a bottom side. The installation body is equipped with a covering element that is rotatably mounted on the top side of the base body and covers the latter in the first rotary position relative to the base body and allows access to the passage holes in the second rotary position relative to the base To meet aesthetic requirements and prevent visibility of parts of the subconstruction, the bottom side of the base plate is equipped with a lower covering. The covering element and the lower covering part fully surround the base body in the first rotary position of the covering element.