Take the guesswork out of rolling the right size fondant, pastry and other doughs with the handy Cake Boss 23.5? by 15.75? Silicone Baking and Fondant Prep Mat. Cake Boss Countertop Accessories make baking and decorating easier and more enjoyable for both novice and experienced bakers and this silicone prep mat features convenient measurement guides printed right on the mat. The prep mat includes 6-, 8-, 9- and 10-inch diameter guides, and the mat’s border features inch and centimetre ruled guides.