The foundation of a mattress is key to a long life and proper support. The old fashioned "boxed spring" has gone out the window and replaced with proper, rigid, support of a foundation. Each one is hand built and specifically made to your mattress size to ensure support from edge to edge.
This foundation is commonly used on any of the "American Comfort", "Steel City", or any other standard mattress. It is recommended by the manufacture and the warranty department to use this proper foundation for any item designed specifically for it's weight and size.
Fabrics and color might vary.
For King sized mattresses you will need 2 - Twin XL boxes