Thermco® spirit filled ASTM Thermometers are made in accordance with specifications of the American Society for Testing and Material. Strict manufacturing procedures and quality controls insure full compliance to ASTM E-1. These instruments are made from annealed glass and have been extensively aged for minimal scale error and stability. Many crossover to the IP standard listed alongside the ASTM number. These thermometers were designed for specific testing and can be calibrated to your specific requirements.