A single-use, disposable clinical thermometer pre-assembled in a sheath for use in measuring rectal body temperature.. Available in Fahrenheit or Celsius, each thermometer is non-sterile and bulk packaged.. Each dot changes color from tan to blue at a specific temperature relative to the melting point of the specific chemical mixture in the dot. Each dot changes color at a temperature of 0.2 degrees F higher than the preceding dot. Tempa-DOT PLUS thermometers are sensitive to environmental temperature - see storage conditions. Tempa-DOT Plus thermometers have a two-year shelf life.