I noticed this in the Baker's Toy Shop
It warms as well as cools. So, the natural leaven is just at the temperature the baker wants.
This will be great for those in hot climates where the temperatures often get too hot for the leaven.
Fermenting the leaven at 32C, 90F will favour the lactobacilli which is great if the baker wants to produce a Sour naturally leavened bread (Sourdough).
Fermenting at 28C 82F gives an equal balance of yeast and lactobacilli fermentation. At this temperature the yeast is at its most active and your leaven will come to ripeness more quickly. This is the temperature I most often use and my natural leaven goes from fridge to feed to ready to use in four hours.
Fermenting at 24C 75F favours the yeast over the lactobacilli. This is a good temperature for very mild naturally leavened breads. This is the temperature at which I often ferment my dough. The lower activity levels give longer bulk fermentation times and thus a better bread flavour.
I don’t need one of these as with the odd exceptional summer days I have to warm my dough and starter and not cool it. I use a Brod and Taylor proofer for that. They are now very expensive and I have written on this forum how to make your own much more cheaply and no DIY skills are needed at all. Cost about $70.
That said, if you find a wodge of $ tucked down behind the sofa / couch and you live in a hot climate? This might be the toy to get.