I bought a Dutch oven for baking my sourdough. (I also just wanted a Dutch oven...) The idea behind the mat is it takes the place of parchment paper. This particular mat is round, but has long tabs on the sides so you can lift it loaf up out of the 450 degree Dutch oven. I think I'll be able to use it to lift stuff out of my Instant Pot too.I use a pizza stone for my sourdough. Let me know how the silicone mat works.
I looked in the Sonoma store in the mall, and they didn't have this shape, just the rectangle mats.