This light can be synced as an accessory to NGTs Dynamic wireless bite alarm set.
The central LED colour can be matched to those on your alarm and receiver so that you know which rod is going off.
At the same time, the surrounding LED's will light up in white providing instant light at night.
The light is adjustable and can be set to stay on for 10, 20, 40 or 80 seconds.
It can also be used as a standalone bivvy light. 
It's easy to attach to the bivvy using the magnets and backing plate included.
Requires 3 x AAA batteries not included.