# The Traffic Signs Regulations and General Directions 2016, Paragraph 12

Extent: E+W+S

The external part of a stud that is visible when the stud is placed must be—
(a) the colour of the reflectors or retroreflecting material (where used);
(b) white;
(c) of a natural metallic finish;
(d) of another neutral colour;
(e) clear; or
(f) any combination,
but when the stud is in place temporarily during road works it must be fluorescent green-yellow except to the extent it consists of reflectors or retroreflecting material necessary to reflect the colour required under paragraph 10 or 11 or it is necessary for it to be a different colour or clear in order for the stud to emit, by a light source, the colour of light required under paragraph 10 or 11.

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Source: https://www.legislation.gov.uk/uksi/2016/362/schedule/11/part/6/paragraph/12 (the official version)
Page: https://openlegislation.uk/traffic-signs-regulations-and-general-directions-2016/schedule-11/part-6/paragraph-12
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.