icebreaker anatomica boxer + fly - men's black, m icebreaker the icebreaker men's anatomica boxer + fly combines a trail-worthy performance with comfort you crave every day. its merino wool blend offers long-lasting softness, and it's thermal-regulating, moisture-wicking, and quick-drying for a solid performance while backpacking. merino wool is also naturally odor-resistant for a touch of freshness when there isn' a washer in sight.