Can someone explain to me about the C02 Extract that I use for my vape pen

I am a medical marijuana patient, and proud, and got a vape pen about two months ago. I have been buying these c02 extract cartridges and been wondering how the hell they do this. I don't understand what type of compound I am medicating with.

Any insight?

How about a link or other clue to get us started?

your basically bypassing all plant matter and collecting the trichs only