The "rez" is the residue.

Now - this is the truth.

It has a VERY small amount of THC. Very small. And the reason is fairly obvious. At a certain heat THC is vaped away - gone. Now that residue resin is the tar in the smoke and the plant matter. For it to get to that point, it's been very hot, and vaped a hell of alot of the THC away.

That's why it's hardly got any THC in it, not to mention all the carciogens and just plain tar in it.

I wouldnt personally smoke it - but some people do and get high from it - more power to them i say. I personally think it's more placebo than anything - but does it matter? If you feel high it works.