The following is an excerpt from cotta's website: "When you bake cookies using a Silpan, the mesh-like processing allows excess oil and moisture to escape, resulting in a crispy texture. Also, the dough doesn't puff up, resulting in a smooth finish. Outer dimensions: 240 x 360mm (edge width 20mm) Material: Silicone, fiberglass Oven safe Heat resistance: 250°C Cold resistance: -40°C" We will lightly fold it to ship so that it doesn't crease. cotta Oven sheet