Pit firing is when you make a clay piece but instead of firing it in a kiln you wrap it in foil along with other burnable items and place it in a real fire! The Foil Saggar is what the finished piece of pottery looks like after it's done being burned. The first picture is what it will look like as the Foil Saggar. The picture below it is the process of the pit firing.
Note: I don't have a photo of my plans because those got deleted by accident. Below is the process of my piece being made, it's before I rubbed it with floor wax, still all dusty from coming right out of the firing pit.