The REIN 3.0 thermal management intervenes when the external temperature of the light head reaches 145-150*f as measured with a laser temp gun.
The Surefire cuts output roughly in half at 100*f external temperature.
This is the reason for the disparities later in the video past initial start-up, as the Surefire reaches these temperatures after 1-2 minutes, while the REIN 3.0 reaches its threshold at 3-4 minutes, and cuts its output by roughly half, as well.
As a test, the Surefire light head was artificially heated to 110*f external temperature via heat-soaking it over a heating vent, but it was not noted to cut power from this.
![](https://s2.save4k.ru/pic/jeti7XuqUto/maxresdefault.jpg)