21″ Round X 3/4″ (533 mm x 19 mm) full kiln shelf. Buying extra shelves gives you the flexibility to load your ceramic ware efficiently and take advantage of the space available. With experience, you will find that loading a kiln is like putting together a three-dimensional puzzle. This is another enjoyable aspect of firing a Paragon kiln. Paragon’s cordierite shelves are volume-stable.