The quality control needed for stove liners is different from that needed for pots. This is because pots can
be all different sizes or shapes, and they will still work well. The Upesi stove has been carefully designed to
be as efficient as possible, and so each liner must be accurately produced if it is to work efficiently. There
are certain points in the production process where quality control is vital. These points have been marked
in the text with the symbol: