The zone long sleeve crewe features icebreaker bodyfitzone construction which combines lightweight 200gm stretch merino wool with strategically placed merino mesh panels to help regulate temperature during stop and go days on the trail or in the mountains flatlock stitching eliminates chafing during day after day of dynamic motion icebreaker bodyfitzone targeted temperature control icebreaker39s new base layer features innovative heat dumping zones mapped against your body to balance