The slot number or instance of a particular component. Typically, if the component plugs into the chassis, this represents the slot number. However, some components are connected to another component, and this represents the instance. For example, a blade may have several expansion cards that connect to the blade system planar, and in this case, this value identifies which expansion card instance the row represents. Note that this slot/instance value can be determined from the componentInventoryTopologyPath object, but this componentInventoryInstance object is provided as a convenience to the user.