A foundation, constructed of spruce (framework) and elements of welded steel, the Beautyrest Harmony Lux Foundation, delivers great support and durability, for the corresponding Beautyrest mattresses. A purchase of this flat foundation, validates the warranty for the Beautyrest mattress it supports, and can also help extend the life of it. The foundation is covered in a coordinating fabric, and meets the state and federal fire retardant standards which are required by law.