A device is provided having a housing with a housing wall consisting of a non-transparent plastic with an outer surface and an inner surface; and an operating mode display unit with at least one light-emitting element which is/are located inside the housing, underneath the inner surface of the housing wall. The housing wall has at least one recess in the area of the light-emitting element and the light intensity of the at least one light-emitting element is adjusted in such a way that in its light-emitting mode, said at least one light-emitting element is only optically perceptible in a localizable manner through the housing wall in this area.