Water Activated Emergency Light (WAELS)
Originally designed for use by SOCOM, the HEEDS light is a water activated LED beacon light intended to guide personnel to emergency air bottles in the event of a vehicle being submerged in water.
The standard version has a Lithium battery and a 5-year standby life. If the Lithium is a problem, then a newer alternative has an option for an alkaline battery (although use of an alkaline battery will restrict the operating temperature range). The light source is an LED, with a very wide viewing angle.
This safety light complies with the 0.75cd output specification and 8 hour duration required by IMO SOLAS regulations.