The light is activated upon contact with water; the activation is immediate and absolutely reliable. For the source of power is an electrolyte cell whose chemical process is initiated by water penetrating it. Further advantages: production of energy which is more environ-ment friendly than the use of batteries as well as easy maintenance.

The fixed light has a duration of 12 (8) hours. In darkness it can be detected from a far dis-tance. So it is a fixture contributing actively to safety, for the shipwrecked person has thus an additional possibility of attracting the attention of the rescue services. This in turn raises considerably the chances of swift rescue and survival - in particular when low water tem-peratures mean that every minute counts.

With the lifejacket light persons in distress are more easily sighted.