You can activate the PCM inserts by exposing them to any temperature lower than their target temperature:
For the blue inserts this is 15 °C (59 °F). and for the yellow inserts it’s 21 °C (70 °F)
The time needed to fully activate the PCM depends on your cooling method: Ice water: 20 minutes, freezer: 40 minutes, refrigerator: 60 minutes.
The 15 °C (59 °F) inserts take a bit longer to activate compared to the 21 °C (70 °F).
Regardless of your cooling method, you can shorten the activation time by laying the inserts flat in a single layer instead of stacking them. If you use the inserts straight out of a freezer, they might feel uncomfortably cold to wear. That is why we recommend waiting at least five minutes to give the inserts time to warm up to their target temperature of 15 °C (59 °F) or 21 °C (70 °F). Once the PCM has reached this temperature, it will stay at that temperature for hours. Inserts that have been activated in a refrigerator or cold water can be used instantly.
Activated inserts can be stored in a cooler or cool box to keep them cool and ready to use for up to twelve hours. If you plan to store PCM inserts in a cooler and/or cool box, we recommend activating them in a freezer.