it's a Truc Clean, simple and portable. I'd go for a self build option if they'd only make one, and given that this is by far the most popular thing I've ever posted, it seems I wouldn't be the their only customer!
It is called the swedish fire log. pour and soak for a few days or weeks. then when you need it start it on fire and you have a fire log that last for hours. we did this in the snow when we had parties or people over to keep warm.