"Pure Cap" is a liquid food additive whose purpose is to make things hot. It is not a sauce or a flavoring, and does not change the way food tastes. All it adds is heat.
Pure Cap has two ingredients: vegetable oil and capsaicin. It claims a Scoville rating of 500,000, which is about equivalent to the hottest habanero. Unlike the pepper, however, Pure Cap has no bright festive color to warn the diner.
The stuff's outer packaging is an orange plastic bottle, like the ones pharmacies use for prescriptions. Inside that is a small glass bottle containing the actual product, with a dropper for applying small amounts. (You really don't want to use too much. Trust me.)
I got some of this stuff from Figuero's, in St. Charles, MO. I had to sign a disclaimer saying that I was not under the influence of alcohol, and that I didn't plan to do anything stupid with the product-- like eat it.