A new colour‐perception lantern shows red, green, and white lights which are within current international chromaticity limits for signal lights in all forms of transport, at three levels of luminous intensity. The light source, filters, and power supply have long‐life characteristics and the whole lantern is intended to be maintenance‐free. The operator's functions are simple and clear, and a fixed routine is proposed for the colour‐perception test. There are two models, Type A approved for the British Armed Services and for Civil Aviation, and Type B approved for the Merchant Navy.

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