Orton cones are for Dawson kiln setter. Each cone number denote a specific firing temperature and is for single use. It will progressively bend to trigger the kiln sitter arm to shut down upon reaching the desired firing temperature. In event of electricity interuption during firing, replace with a new cone to refire. All cones are for single use only.
Knife smiths uses these as witness cones to gauge furnace temperature for annealing, hardening or tempering.