Help ensure cold chain accountability with these WarmMark™ temperature indicator tags. If the tag is exposed above its response temperature (-18°C/0°F to 37°C/99°F), the chemical in the pad melts and begins to migrate down the track strip and color in the circular windows at a controlled rate. When the temperature falls below the response temperature, migration of the chemical stops. Tag accuracy is guaranteed to be +/- 1° to provide an easy-to-read indication that the shipment has been handled and stored properly throughout the supply chain. The WarmMark™ Time/Temperature Tags for 8°C/46°F (Item: WM25046F) help ensure the Center for Disease Control (CDC) temperature requirements for shipping and storing Coronavirus (COVID-19) test samples are maintained. The simple, accurate indication of temperature excursion helps ensure the test samples have stayed within the 2°C-8°C range.