Product review (5 stars): Using as a freezer-fail alarm
I am using this switch to indicate when my freezer gets too warm. It's supposed to be at 0F (about -18C). This switch is closed below -7C (12F), and open above that temperature.

I've hooked it up to a Z-wave door sensor, and if the freezer gets too warm, I get a text on my phone. Works like a charm.

As for other purposes - - the switch is properly made, well-sealed and terminated with bullet-style contacts. Since it's mechanical (bi-metal thermal switch), it should last a long time.