Though this kitchen tool is used mainly to roll out dough, it's also handy for a number of other culinary tasks including crushing crackers and bread crumbs, shaping cookies like tuiles and flattening meats such as chicken breasts. Rolling pins can be made of almost any material including brass, ceramic, copper, glass, marble, plastic and porcelain. The favored material, however, is hardwood. The heavier pins deliver the best results because their weight and balance produce smoother doughs with less effort. There are many rolling pin styles but by far the most popular and easiest for most people to use are the American or bakers' rolling pins. Those of higher quality are characterized by sturdy handles anchored with a steel rod running through the center of the pin and fitted with ball bearings. Many professional cooks prefer the straight French rolling pin (a solid piece of hardwood sans handles) because they get the "feel" of the dough under their palms. The tapered rolling pin is larger in the center and tapers to both ends, which allows it to be rotated during the rolling process — a feature particularly useful for rolling circles of dough. There are also "cool" rolling pins made of ceramic, marble, glass or plastic, some of which are hollow and can be filled with ice or iced water. These special-purpose pins are designed to work with delicate pastry doughs that become difficult as they warm.