Abstract: This disclosure addresses mattresses. The mattress includes a core made up of multiple zones. Each of the zones includes a plurality of core elements, the core elements being formed from at least one wire coil spring at least partially contained in a fabric pouch. The core elements are typically joined in linear chains. The zones vary in support firmness according to the selection of a user. The core elements include wire coil springs formed from wires of at least two different sizes, and of at least two different heights.