Text in force at CS29-12: from CS29-0, effective 14 Nov 2003.
For each instrument:
(a) When markings are on t he cover gl ass of the instrument there must be means to maintain the correct alignment of the glass cover with the face of the dial; and
(b) Each arc and l ine m ust be wide enough, and located to be clearly visible to the pilot.
ED Decision 2003/016/RM · Source