6-cavity square muffin pan, often used for baking brownies, cupcakes, or mini loafs. It appears to be made of a dark, non-stick material, possibly carbon steel or silicone. The dimensions of each cavity are likely around 4 inches, although sizes can vary. These pans are designed to produce evenly baked goods with a uniform shape and are easy to clean. Some models are flexible, while others are more rigid. It's advisable to place silicone pans on a baking sheet before filling them to prevent spills. While typically non-stick, greasing the pan can further ensure easy release of the baked goods.