It is mostly propylene glycol. It's not really a bad price, considering that pure propylene glycol is running about $45 per gallon. Pure propylene glycol has a boiling point of around 370 degrees F. In the same way that pure ethylene glycol doesn't cool as well as a 50/50 mix with water, propylene glycol doesn't cool as well. I don't know if its a lower specific heat or heat transfer coefficient.
Freezing temp of pure is -59 degrees F.

It's mildly toxic. I'd have to ingest 5 1/2 pints to have a 50% chance of dying, but I'm pretty big.

I often think these little groups of true believers are like religious cults. They believe, regardless. Maybe you're coming out into the light.

R.