FibraMent-D Rectangular Home Oven Baking Stone Three Sizes (13.875 x 17.5" Ship to Lower 48 States) The size of our baking stone is 13.875 x 17.5 . Made in the USA of a blend of heat resistant and conductive materials approved by NSF International for use in baking ovens. Be sure to measure your oven before ordering. Allow at least a one-inch opening on each side of the baking stone for proper air movement. Easy Maintenance! Never wash this stone--just scrape excess spillage. FibraMent-D never needs to be removed from your oven, bakes the perfect pizza, breads, cakes, cookies, etc., every time and easy to follow baking instructions are provided. Designed for gas, electric and convection ovens, it can be placed directly on your oven rack. Why keep a Baking Stone in your oven? As you bake, your oven cycles on and off, causing the temperature to fluctuate as much as 20 degrees F above and below the temperature you set. The Baking Stone, when placed on a lower shelf about 5 inches below the oven floor provides instant even heat when bread is placed directly on the stone as well as stabilizing the temperature in the oven.