Used to make earthenware windowbox.
Note: The earthenware windowbox is made using the build menu rather than using the kiln's use button.
Real World Context
Earthenware is a kind of ceramic stoneware that is "non-vitreous", meaning that it hasn't been turned into a kind of glass. Basic earthenware, often called terracotta, absorbs liquids such as water. However, earthenware can be made impervious to liquids by coating it with a ceramic glaze.