The LYNX V3S is a countdown timer system designed to monitor the awareness of the officer of the watch. Basically it flashes a light & makes noise at pre-determined intervals to make you press a button to ensure you haven't fallen asleep at the wheel. There's a built-in key switch to stop the guy on watch turning it off.
It's powered by 8 to 32v DC, so works on either the 12v or 24v system.
It has 3 stages of alarm -
Audible alarm using its internal buzzer
Audible alarm using an external siren
The time period can be set between 3 to 12 minutes before the visual alarm starts. The visual alarm runs for 15 secs before the internal buzzer starts. It then runs for 3 mins before the siren is triggered.