The IceBreaker Apex Leggings w/ Fly are made from an amazingly soft, breathable 260gm pure merino jersey that keeps you really warm during cool to cold weather sports. Built to move, with a crotch gusset and flatlock seams, the Apex leggings are a great baselayer for active winter sports, or hiking or running on cold mornings in shoulder seasons. You can bring one pair on a multi-day backcountry excursion, because the natural odor prevention of merino keeps them fresh for multiple wearings.Features:Functioning flyGusset for comfort and mobilityNo center back seamIcebreaker branded brushed elastic waistbandWhy 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 the same for you.