Okay, I have received the thermostat. I have it set up as I type. It appears to be a decent on/off thermostat. The only issue I can see if if anyone is using aspen bedding as a substrate. The unit cannot reach temps any higher than 108 degrees. This may not allow the tub temp to get to your determined temp. Since I don't have any tubs with aspen, I can't test this.
This thermostat turns on 2 degrees lower than that turn off temps. I have it set up at 105 degrees. This means the unit turns on at 103 and turns off at 105 degrees. I am using the 3 inch 10 watt tape. Your settings will vary. You will have to experiment with this unit to get your temps properly set inside your tubs. My temps are only for experimentation only. I do not have any snakes living in tubs at this temp.
I don't think anyone could go wrong buying this unit for $30. Just remember the upper limit of this thermostat is 108 degrees. So, if you use a thick layer of aspen or any other substrate, it may not allow the temps to your desired level.
Jim Smith