4.—(1) The pyramid must consist of three visible sides, each of which is as specified in the diagram.
(2) It must be made of rubber or flexible plastic material.
(3) It must be constructed so that it can stand upright firmly on the surface of a road.
(4) The surface coloured red (marked A and C) may be reflectorised.
(5) The surface coloured white (marked B) must be reflectorised.
(6) Up to 50% of the surface marked C may be obscured by constructional components.
(7) The pyramid must not be illuminated through internal or external illumination.
(8) The base may be of any colour, or omitted.