housing is Aluminium, afair,
BUT
there is a reason
not a single bike light producer still promotes its HIDs (in the 10 W range):
they were crap when they were space-age technology - some 2-3 years ago - and now are even more crap.
With the quad-led getting used by manufacturers in raising numbers, there is nothing a HID bike light can do better.
And both consume about the same power.
There is only one thing a HID is freaky --> statup show.
and the BigBang is allowed to be used as official street-allowed bike illumination, of course.
(with all the cons, that pro is a very specific point, but if someone cares ...)
PS: Lupine Tesla, or the Tesla clone at DX, both are much better than any 10 W HID bike light ever produced