This is a simple product: Mugs designed specifically for camping or hiking. These Finex portable travel mugs use carabiners instead of traditional handles that allow you to quickly clip the mugs to your pack (or anything else, for that matter).
The mugs are made with food-grade stainless steel, and are double walled for better insulation. Now your campfire coffees will stay hotter longer.
You can snag a set of two for $16.