4.—(1) The yellow bands on the pole may be illuminated by means of retroreflecting material.
(2) The parts of the roundel coloured black shall not be illuminated by means of retroreflecting material.
(3) Subject to paragraph (4) below, the parts of the roundel coloured yellow shall be fluorescent.
(4) With the exception of the parts coloured black and the perimeter strip, the roundel shall be illuminated by means of retroreflecting material, but retroreflecting material applied to the parts coloured yellow shall, if that material is not fluorescent, be applied in horizontal strips with gaps between the strips.
(5) The parts of the roundel coloured red may be fluorescent.