The features, conventions, characteristics and attributes identified in this guide are those of magnetic contactors and thermal overload relays. These are components which may be used alone, or combined with other components, to serve as full-voltage or reduced-voltage, reversing or non-reversing, single-speed or multi-speed motor controllers. Control products compared or contrasted in this guide are those with equivalent electrical ratings; such ratings are expressed via nameplates, catalogues, or technical literature.