Pyrometric cones are composed of clay and glaze material, and are designed to melt and bend at specific temperatures to determine the conditions of a kiln. Cones are a better indicator than temperature alone as the degree of glaze melt is a combination of time and temperature heat work. A fast firing needs to go to a higher temperature to get the same results as a slow firing to a lower temperature. Low fired ceramics are generally fired to Cone 1 or 2, high fired can go to cone 6 to 10.