Typical temperatures for commercial models are in the 250F range with a max of 300F. There are also plans online for DIY solar ovens like the $5 oven.
A folding oven is a stamped metal box that folds flat for storage and unfolds into a box for stovetop baking. The most famous example is the Coleman folding oven.
Most types have a built-in thermometer and rely on stove output to regulate temperature. Because of their small size and light weight it can be difficult to keep an even temperature; lower flames are easiest to adjust.