Sheet pans, also known as baking sheets or cookie sheets, are flat, rectangular metal trays used in ovens for baking and roasting. They typically have low sides, which allow for easy access to food and promote even cooking. Sheet pans come in various sizes, with the most common being the half-sheet pan, measuring about 18 by 13 inches. These versatile kitchen tools can be used for a variety of tasks, including baking cookies, roasting vegetables, and even making sheet cakes. Made from materials like aluminum or stainless steel, sheet pans are durable and easy to clean, making them a staple in both home and professional kitchens.