Fitz-All Heat Diffusers For Use On Ranges To Protect Glass Cookware, Card of 2 Fitz-All's Heat Diffuser grids are made of heavy gauge metal Designed to protect glass coffee pots and tea pots on both electric and gas ranges Can also be used under metal pots and pans to reduce sticking and burning of food or eliminate scorching of cookware Each Diffuser Grid Measures Approx. 3-3/4" X 3-3/4".