Thermolock® Marker 80Thermolock® Marker 80
How to Detect Heat Generation with Thermolock®How to Detect Heat Generation with Thermolock®

Thermolock® is a heat sensitive color changing pigment that performs a semi-permanent color change in which a color disappears and is locked in at or above a threshold temperature. Additionally, the original color will not return under ordinary, daily conditions, but only if the temperature is lowered dramatically.

Some possible uses may include temperature control indicators, which were previously difficult to specify on the original Chromicolor, as well as security products and sensors.



  • Please shake the pen several times before using. Press the tip of the pen slightly and continue to press it for a while to make sure that the ink is fully distributed to the tip before using.
  • After initial usage, please shake and click several times before using.
  • When color starts to fade, please press the tip of the pen firmly after shaking it vigorously to produce ink. Please be cautious of applying too much pressure.
  • Please make sure to close the cap of the pen when not in use. If the tip of the pen becomes extremely dry, it should be disposed.

While conventional Chromicolors® repeat reversible color development and color disappearance due to temperature, newly developed Thermolock® is a heat sensitive color changing pigment that performs semi-irreversible color change where color disappears and is locked on or above at the Locking Temperature Upon Color Disappearance. Also, the color will not develop again under temperatures in daily life conditions.



  • Please do not use for other than writing purposes.
  • Not suitable for usage on chloroethlyene products, certain rubbers, packing tapes, and Teflons.
  • Due to the ink containing flammable products, please do not use near fire. Do not incinerate as a means of disposal. Please use it under ventilated conditions when used for a long period of time in a closed room.
  • Do not leave the pen where direct sun light and high temperature is predicted. Also, keep out of reach of children. If swallowed, get medical help or contact a poison control center right away.
  • Since the ink has a poor ability to resist light, please make sure not to expose the pen or portions written by the product to direct sun light. (This product is designed for indoor use and within a box usage.)
  • Please note that letters written by this product have weaker adhesiveness than that of normal inks. Thus, it may peel off if scratched by hard objects such as adhesive tapes or finger nails.
  • When a room temperature becomes -25°C, it may return to its original color.*
  • A shelf-life of the product is one year after its production date.
*We are not liable for any accidents or complications after usage
*We reserve the right to change its specification for improvement without any notification in advance.

How to Detect Heat Generation with Thermolock®