Made from a light soft breathable 200gm rib fabric it feels great as a stand alone shirt layers really easily under another top in cooler weather and provides great insulation worn under a shell so pack an everyday crewe it39s the shirt you really want to wear everyday why icebreaker merino the merino is an ancient breed of alpine sheep over millions of years they evolved a superfine highly breathable fleece to protect them from freezing winters and scorching summers it will do th