A firm 11.5″ mattress. The Tempurpedic Achieve Mattress has adapt comfort—the nothing-else-like-it, pressure-relieving comfort and precisely aligning support. Soft where you want it, firm where you need it. comfort and support with the TEMPUR-Achieve. Moisture-wicking cool-to-the-touch advanced fabric cover and an integrated phase change material beneath the surface for increased comfort.