Very soft base-layer with bamboo for softness on the inside and merino wool for warmth on the outside. The most comfortable base-layer we have.Why freeze, if you can be warm? The secret of this Reima base layer set is a double-face knit: a soft, silky bamboo viscose against the skin to absorb moisture and give a smooth feel, with wool on the surface for the best possible warmth at the base layer. The bamboo viscose absorbs moisture away from the skin and helps kids feel fresh. The wool keeps kids warm, even if they become sweaty after busy play. This combination in a kids' thermal set is ideal for thermal comfort - both indoors and outdoors.