ML20.a omfatter mobile systemer, der indeholder eller anvender tilbehør eller komponenter fremstillet af ikke-metalliske eller ikke-elektrisk ledende materialer, såsom plast eller epoxybehandlede materialer.
ML20.a. includes mobile systems incorporating or employing accessories or components manufactured from non-metallic or non-electrical conductive materials, such as plastics or epoxy-impregnated materials.