Primo Natural Finish Fredstone Oval Baking Stone for Oval XL 400, 23x16-Inches lets you achieve brick-oven quality for a fraction of the price on your Primo grill. Invented by Danish baker Frederik Sørensen, this lightweight, porous ceramic stone helps you grill the perfect pizza with any of the larger Primo grills. It makes an excellent tool for any BBQ enthusiast looking to expand their grilling repertoire.