Simmons Natural Care Latex Patterson Firm California King Mattress Certified mattress provides firm ergonomic support Rubber tree-derived latex foam core is naturally durable, hypoallergenic, and dust-, mite-, mold-, and mildew-resistant Breathable knit top fabric made from cultivated white pine fibers Wood foundation typically sourced from companies who participate in the Sustainable Forestry Initiative Please note that the box spring is not included