| 摘要 |
A marker suitable for use under conditions of sudden darkness comprising at least one phosphorescent indicium which provides a relatively high level of illumination for a relatively short period of time following exposure to light, sufficient to permit a person's eyes to adjust to darkness and at least one tritium illuminated indicium providing a relatively low level of illumination for a relatively long duration, which level of illumination is sufficient so as to be seen by a person once the person's eyes have adjusted to darkness.
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