Medical Indicators' thermometers are made of thin
plastic material with an encapsulated matrix, of harmless, non-toxic
chemical dots that when read, represent a specific temperature.
The dots are a bright green color at normal room temperature.
As the thermometer is warmed, the chemical dots turn black in sequence
until the highest temperature is reached. When the thermometer is
read, the highest black dot temperature determines the subject's
actual temperature. The chemical dots will revert back to their
original green state in a short period of time, so the unit can
be reused, or thrown away according to directions.