Under the Snuggle-Pedic Mattress cover is 2 layers. The 1st layer is 3 inches of Snuggle-Pedic’s proprietary Snuggle Flex ventilated memory foam. The support layer is 7 inches of high density polyurethane foam adds support and airflow throughout the sleep experience. Thousands of small surface holes connect to airflow channels to create a full airflow circulation. These channels pull the heat directly from the sleeper’s body so they have a cool sleeping environment throughout the night.