I assume xenon is better, kind of like the expensive cars that give off the bluish tint? I noticed Surefire lights are xenon and insight aka M3 and etc. are halogen. Any really advantages except for price? And is a 65 lumen xenon comparable to a 90 lumen halogen?

Thanks.

I know Xenon is way more expensive.

Xenon is one of the inert gasses that can be used to fill a bulb. A halogen gas (such as bromine) can be added to cause a redeposition of a portion of evaporated (read "lost") tungsten back on the filament at high temperatures. This is done to extend filament life. There's a brief discussion of the tungsten-halide cycle included in the write-up
[url]http://www.gilway.com/html/appl-tungsten.html[/url]

(BTW, these are not my words. I'll see if I can find the post I stole them from)

Al