Warm High

  •   Colors permanently when exceeding threshold
  •   Self-adhesive backing for easy attachment
  •   Clear readings
  •   Available from +29° untill +290°
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General information

The Warm high indicator

The Warm High (WH) indicators are based on proprietary color change technology to provide a clear and simple temperature monitoring system. IntroTech Irreversible WH indicators give users the power to know whether their goods were subjected to unacceptable temperatures – and by how much.


The Warm High labels consist of a series of temperature-sensitive elements sealed between heat-resistant substrates with a transparent window. Each element distinctly changes color from silver to black as its rated temperature is reached or exceeded.

The compact self-adhesive indicators are sized 12 x 13 mm and can be easily attached like labels to any sensitive product. They are both oil and water-resistant.


IntroTech’s Warm-High Irreversible Temperature Indicator uses temperature-sensitive elements: phase-change indicators that use the sharply defined melting points of a series of specially purified organic chemicals to produce a series of unique, high precision, color change effects. Each temperature element uses a different chemical compound and is made separately by applying a coating containing the chemical to a special absorptive paper substrate. Up to ten elements can be combined together on a single label.

When the rated temperature is exceeded, the chemical melts and is absorbed by the substrate, causing a permanent color change. The Warm-High Irreversible Indicator is available to cover a wide range of temperatures from 29°C to 290°C (see Technical Specifications).


Irreversible Warm High Temperature Indicators from IntroTech provide an ideal solution to safeguard temperature-controlled products: aclear, simple and reliable one-time label that can be quickly and securely attached to each product to protect it on its journey. When removed, the labels will not delaminate, which means they can then be attached to inspection report to provide permanent verification following shipment or storage.

How does it work?
The temperature-sensitive elements are phase-changing indicators which make use of well-defined melting points of a series of specially purified organic chemicals in order to give it a unique, highly accurate, color-changing effect.

Each temperature-sensitive element uses a different chemical element and is manufactured individually by applying a coating to that element on a special absorbent paper medium.

If the specified temperature is exceeded, it melts the chemical element, and is absorbed by the absorbent paper wear which has as a result a permanent change in color.

A WH-label can provide very accurate results because there up to ten different chemical elements can be combined on a single label.

The Warm-High is available in the range of 29°C to 290°C, check the technical specifications for more details.

Technical specifications
Available temperatures:
29/33/34/37/40/42/43/44/46/49/54/60 °C
62/65/66/71/77/80/82/88/93/99 °C
104 / 110/116/121/127/132/138/143/149/154 °C
160/166/171/177/182/188/193/199/204/210 °C
216/224/232/241/249 / 254/260/280/290 °C

These self-adhesive labels include

  • self-adhesive labels
  • immediate response
  • oil, water and steam resistant
  • Hot High-label dimensions: 12x13mm

Accuracy tolerances:

  • is below 100 °C +/- 1 °C
  • 100 °C to 154 °C +/- 1.5 °C
  • above 160 °C is +/- 1% + 1 °C