Any UTH including this one needs to be regulated with a thermostat. Reading the description, it says it has an auto off feature in case of extreme temperatures, this is not sufficient, it needs to be regulated with a thermostat.
With that said....
I personally have never used cork as a substrate but as long as it is not a flammable substrate around the 90 degree marker, I don't see why there would be an issue.
Also this UTH seems to imply the pad goes on the inside, Any heat pad should always go on the outside of the enclosure go the safety of your balls.
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