Explore Ashcroft thermometers for your specific application. Ashcroft bimetal thermometers and gas actuated thermometers provide easy-to-read temperature measurement on a dial indicator. Both operate without the use of mercury. Bimetal thermometers are actuated by a helical bimetal while gas-actuated thermometers use expanding or contracting gas in a closed bulb and capillary system. Bimetal stems and capillaries along with associated thermowells are available in a wide selection of lengths to fit nearly any application