Powered by Hexon Heat Technology, the Milwaukee Heated Merino Wool Crew Neck Baselayer provides Next To Skin Heat with Fewer Layers. The Heated Crew Neck Baselayer delivers up to 8 hours of runtime across two heat zones-chest and back-with adjustable settings ranging from high to low. Kitted with the Heated Gear 2.5Ah Battery with App Control, it integrates seamlessly with the Heated Gear App and provides a comfortable experience thanks to its ergonomic design. The premium merino wool-polyester blend fabric offers superior stretch, moisture control, odor resistance, and temperature regulation. This base layer offers a balanced fit with a regular cut, neither too tight nor too loose.