NightTherapy 3" Memory Foam & Latex Mattress Topper (California King) SIZE: California King. 1 1/2" Highest Quality memory foam layer cradles your body with special 5-Zone comfort areas 1 1/2" Natural latex layer provides the subtle firmness for the support you need Reversible so you can personalize your comfort. Use with the memory foam side on top for lumbar, and alignment support. Use with the natural, ventilated latex side on top for cool, subtle firmness Natural odor protection from green tea extract. Anti-microbial properties from real silver particles Fabric encasing the topper & skirt is real bamboo fibers, which is a sustainable ingredient