Designed for hunting in forested elevated locations, the CORE Heavyweight Half Zip from Sitka Gear is perfect for warm, mild, cool, cold and extreme cold conditions. With lofted fleece insulation and a high zippered neck for fine-tuning your microclimate, the CORE Heavyweight Zip-T keeps you toasty on frigid, low-activity hunts. Permanent Polygiene Odor Control Technology neutralizes odor by stopping the growth of odor-causing bacteria and fungi. The CORE Heavyweight Series is the next-to-skin foundation for static hunts in cold weather, with a body-mapped grid fleece backer that retains warmth while actively moving moisture away from the skin.