An arbitrary string that uniquely identifies the physicalelement and serves as the element's key. The Tag property can contain ...

An arbitrary string that uniquely identifies the physicalelement and serves as the element's key.  The Tag property can contain information such as asset tag or serial number data. The key for CIM_PhysicalElement is placed very high in the object hierarchy in order to independently identify the hardware/entity, regardless of physical placement in or on cabinets, adapters, etc.  For example, a removable component that can be hot swapped, may be taken from its containing (scoping) package and be temporarily unused.  The object still continues to exist - and may even be inserted into a different scoping container.  Therefore, the key for physicalelement is an arbitrary string and is defined independently of any placement or location-oriented hierarchy.