These Freezer thermometer cards operate in the range -25°C to +1°C dimensions 120mm x 60mm The Liquid Crystal Thermometer Strip is a 100mm x 12 mm temperature sensitive strip with 5mm high easy to read numbers. This Thermometer card has the following temperature pockets -24 -21 -18 -15 -12 -9 -6 -3 0°C
When the temperature is 1°C below the pocket temp the digits are blue.
When the temperature is 1°C above the pocket temp the digits are brown.
Therefore this card reads from -25 to +1°C
These thermometer cards are very sensitive and are best attached to metal shelf/draw fronts, side walls where the effects of the in rush of warm air from outside of the freezer can be reduced or in applications where they can be observed without opening the freezer door/draw e.g. Ice cream freezers, Clear fronted draws in domestic freezers etc