These are all the rage in professional baking circles. They are thin mats of pure silicon that are placed on a baking pan (they come in the sizes that commercial pans measure, 12 x 18 inches being the smallest) to provide a perfectly nonstick surface for baking. Fairly expensive, they may be used thousands of times and only need to be wiped clean after each use. If you like to collect every new kitchenware item that emerges, then by all means get some, though I don’t find that they are so useful for home baking.