The Dual Spring System in the grey base set provides superior back support and adds a longer life to your mattress. Reinforced corner support to create consistent comfort throughout the mattress sleep surface. The exclusive Copper Cool infused high density foam adds natural anti-microbial and anti-bacterial properties. The Copper increases blood circulation which results in less body movement and a deeper sleep. The never turn technology allow you to no longer have to “flip” your heavy mattress, simply rotate your mattress once per month for improved longevity.