This can is just as the name implies. It could be used to keep your hot/hot or cold/cold. Aluminum inside, insulated foam on the outside. It's rather simple to make. It could be used outside or around the house to keep your coffee warm or a beverage cold. You could think of it like your very own coffee coozie :)
If you'll look at the other pictures below, you see that a 12oz. can , 8oz. foam cup and what I used is a military issued p-38 (can opener). You will need a razor blade and book as well. As you can see most of the items you'll find readily at your home.
The comments I was quoting are here: http://www.instructables.com/id/The-Crazy-Cool-Can-Cup-Aka%3B-how-to-turn-a-pop-can/