Enhance your workout with icebreaker's top of the line merino base layer collection. From men's thermal underwear to breathable t-shirts, find lightweight, low bulk shirts and lightweight pants that will never get in the way of your workout. With anti-chafe seams and a touch of LYCRA for added fit, you'll find an extended range of motion like no other workout wear can provide. Find items such as shirts, shorts, leggings, and more, all designed to keep you warm in even the coolest conditions in the icebreaker merino base layer collection. Cover your men's thermal first layer with a lightweight pair of shorts or hiking pants, or check out our base layer and t-shirts collections, as well. Find clothing that is as durable as you are in the icebreaker merino first layer collection.