The metallic compound AuIn2 is useful as a thermometer or a refrigerant in the temperature region below 0.1*K. Its utility extends to the submillidegree Kelvin region. The thermometric parameter is its static nuclear magnetic susceptibility, which is relatively large. The refrigerating technique of adiabatic demagnetization is also applicable to the large nuclear magnetic moments of this material. The product of temperature and spinlattice relaxation time of AuIn2 is approximately constant in this temperature range and equal to 0.09 seconds-*K giving approximately 1 second relaxation time at 0.1*K and 1 minute at 1 millidegree K.