I've spent so much over the years trying to get an off-the-shelf solution working for all my different \"keep it in the happy temperature range\" needs - mycology liquid culture, lacto-fermentation (pickles, kimchi) - sourdough starter, and even for counter-proofing dough on chillier days. Heating blankets, coffee mug warmers - even laboratory immersion baths, I've messed with them all. Obviously a lab bath works great - but it's big, clunky, and not very flexible usage wise (I can't use a mag-stirrer with a water bath, for instance). I'd always planned to build something like this, but never got around to it. I'm glad the commercial world finally did! All that, and the price point is perfect bang-for-the-buck. Super pleased!
handyman 
