Serta iComfortECO Smooth HybridMaterials & Construction With more comfort, support, and sustainability, the smooth hybrid iComfortECO delivers a better night's sleep that's easier on the earth. With eco friendly materials like the CoolTemp Cover Powered by Repreve, a cool to the touch, breathable cover made with the recycled plastic equivalent to 120 water bottles* and Terra Fusion Memory Foam made from 30% plant based material that provides pressure relief, cradling comfort, and