The SOS is a lightstick provided with a cord. When activated, it becomes a particularly practical survival signal light generating a highly visible circle of light. By spinning its handle, a light circle is formed, visible at up to 1 mile (1.6 km) on land/sea level, and 3 miles (4.8 km) from the sky.
This survival signal light is useful as an emergency light, distress light, means of airborne and horizontal identification lighting.
SOS is used in various situations, for instance: