Battery-Operated Temp Sensor for Inside Freezer?

[jlv]

I use an Iris v2 contact sensor in my freezer. The last battery (CR2) lasted 16 months.

Temperature sensors for freezers

I have an Iris V2 contact sensor in my freezer. I’ve got it inside a tiny ziploc bag and use it just for temperature. Depending upon where I put it, it reads between -10°F (bottom) and 5°F (door). It gets about 9 months of battery life (CR2).