Most all potters uses these small cones, which are made of a carefully proportioned mixed batch of ceramic materials that wilt at a certain temperature. In the photo above, taken during in our Wood Fired Kiln, you can see one of the cones is bending, and this is how we can monitor and adjust the temperature we need to get the correct effect. There are different cones for different temperatures. If the photograph below you can see some cones after a successful firing.