A covering that has a means for support, a means for abutment to a wall, and a means for retaining a sensing element. The covering includes a body portion and a perimeter portion with a plurality of radially extending fins. Fins with or without boss are useful for abutment to a wall or surface. One or more means for retaining positioned in the interior of the body, are useful for fixedly positioning or holding a sensing element. The covering may be position on or into a hole and optionally includes additional elements for function and use, such as reinforcing members on the radially extending fins, a central hub, and a spool position around the hub.