Abstract: The present disclosure relates to a dosimeter for measuring exposure to heat over time in combination with peak temperature indicators and reversible temperature indicators. The preferred temperature indicator tag is credit card sized and comprises four time-temperature dosimeters. Each dosimeter has a wick in contact with a separate reservoir containing a mix of a colored dye, a wax and an amorphous polymer to indicate a distinct temperature range when the mix melts. The wicks are preferably made of porous paper with a pore size around 8 microns to allow for proper capillary action along its length. An adhesive, except where each wick contacts its respective reservoir and at a vent, preferably seals each wick. The tag preferably has a plurality of peak temperature indicators where each indicator has a blend of a dye, a wax and a polymer for a temperature indication range. The tag also preferably has a plurality of reversible temperature sensors.