A cover is provided, preferably for securing valves, propellers, door knobs and the like. The cover entails a hinged plate having two sections. Each section contains an indentation which, when the sections are closed, forms an aperture. A pair of arms may depend from each section in alignment with the indentations. When the sections are closed, the arms will form a hollow column in alignment with the aperture. The hollow column will also preferably contain a constriction, preferably formed by a pair of lips extending inwardly from each arm. The sections will also contain sidewalls rising from the sections opposite the hollow column if it is present. A cap is provided which will fit over the sidewalls. A tongue and groove mechanism may be provided to allow the cap to engage the sidewalls and the sections to which they are attached. A plurality of locking apertures may also be provided in the sections and the cap so that the cover may be locked with a padlock. In use the aperture or constriction will close around a thin area on the object to be covered, such as the portion of a valve behind the locking nut, the portion of a propeller hub before its flared end, or the shaft of a door knob. The sidewalls will be sized to surround the object being covered, and the cap will fit over the sidewalls, thereby enclosing the object. If the cover, is locked, the object will then be secured.