Calking Wool Mattress Pad Experience the magic and natural comfort of 100 % lamb's wool. The natural properties of wool have a soothing, cushioning effect, partially because the deep wool pile conforms to the contours of the body, reducing the pressure points on hips and shoulders. Our 100% lamb's wool sleeper has light, soft tips and abundant, dense wool at the base to cradle you and support you in your sleep. Use it under your bottom sheet for warmth in the winter and cool insulation throughout the summer.