No.?4 is our most responsive mattress. It s made with 1600honeycombed pocket springs and 1500 micro springs forthe most comfortable night s sleep. We hand fill the mattresswith pure new wool and cotton. Then we add Pillow Top an extra layer that sits on the mattress surface for even more enveloping comfort. It s filled with the finest natural materials pashmina, soft bamboo, alpaca, cashmere and silk. Underneaththat you ll find further layers of wool that are all hand-tufted tomake sure the mattress keeps its shape over time. It s finishedwith Belgian Damask ticking to create a feather-soft surface wherever you lie down.