The Mobile Warming Longman Heated baselayer shirt is made from 4-way stretch antibacterial polyamide fabric that provides a comfortable next-to-skin feel. The Longman Shirt features side stretch panels to conform to your body and movement. Integrated heating panels keep you warm and comfortable for hours. The ultra-fine heating elements are insulated and designed to provide instant heat on demand. The integrated power button has 4 selectable heat settings and is powered by a light-weight rechargeable 7.4-volt lithium-ion battery that keeps you warm and comfortable for up to 8 hours. Features Available in XS, SM, LG, XL, 2XL, and 3XL; 92% Polyester, 8% Spandex; Antibacterial; Crew Neck; Flatlock Seams; Four Selectable Heat Settings; Integrated Touch Control button; Mesh Side Inserts; Moisture Wicking; Stretch Polyamide Fabric; Tri-Zone Heating Elements Two Chest and One Back; Up to 8 Hours of Heating Per Charge; Includes (1) Mobile Warming Longman Shirt; (1) 7.4volt 2200mAh Lithium-ion Battery; (1) AC Charger;