An innerspring mattress is a type of mattress that uses a core of metal coils to provide support. These coils are typically made from steel and are designed to respond to body weight, offering a balance of comfort and firmness. The mattress is often topped with layers of padding, such as foam or fiber, to enhance comfort. Innerspring mattresses come in various designs, including continuous coils, offset coils, and pocketed coils, each offering different levels of support and motion isolation. They are popular for their durability and breathability, making them a common choice for many sleepers.