Battery heated base layers act as heated long underwear or low-profile heated vest liners. Many brands have heating elements in the chest and back, while base layer pants feature the heating panels at the lower back and thighs. Base layers are best used as an inner layer under your regular shirt and pants. This maximizes heat retention. Base layers, being closest to the skin, offer noticeable heat production when used properly. 

• ActionHeat 5V Battery Heated Base Layer Shirt & Base Layer Pants - Also available in Women's Shirt and Women's Pants. The ActionHeat Battery Heated Base Layers are revolutionary in the world of heated clothing. Using 5V signal technology, they allow for any 5V USB battery to be used with the ActionHeat base layers.  This allows unlimited battery options! The ActionHeat base layers include an ultra-powerful ActionHeat 5V Power Bank 6000mAh. This power bank powers your garment and can also charge your phone, tablet, or any USB-charged device. ActionHeat heated garments use FAR infrared heating and ActionWave heat reflective technology to deliver hours of heat and comfort. These revolutionary garments feature built-in heating panels and are made with ActionFlex material that provides lightweight warmth, comfort, and versatility. ActionHeat allows you to stay warm and enjoy outdoor winter activities longer than ever before!
• Volt 7V Battery Heated Base Layer - This lightweight garment not only provides you with soothing heat but also wicks away moisture, making it the perfect base layer choice. Constructed from micro polyester/Spandex material, the brushed fleece lining makes a comfortable fit. The Zero Layer heating system uses two 7v heating panels that concentrate heat down the middle of the back helping to keep your core warm. Provide soothing heat on high for 2 hours and up to 8 hours of heat on the lowest setting.
• Mobile Warming 7.4V Battery Heated Primer Base Layer & Pants - The Mobile Warming Primer Shirt and Pants for men are versatile garments designed to wear close to your skin under your regular clothing These amazing heated base layers fit comfortably under your favorite outdoor, ski or hunting apparel to provide hours of heat so you can enjoy the cold weather like never before. The wonderful wicking ability make the shirt and pants great layering pieces and a must for any long-term exposure to cold weather. The antimicrobial fabric fights odor and bacteria to keep the garment fresh. Available in women's shirts and pants.
• FNDN Heated Skin-Fit Base Layer Pro & Pants - FNDN brings the heat, straight outta Detroit! Constructed out of a moisture-wicking, lightweight, and stretchy fabric, the base layer top has thumbhole cuffs so the arms never ride up. Four heat settings let you really dial in the amount of warmth desired. The FNDN Pants allow you to easily connect to the FNDN Base Layer Socks and control their heat setting with the same pants controller. FNDN base layers batteries use USB charging and small and lightweight BEGO batteries. 
• Gerbing 7V Battery Heated Vest Liner - The Gerbing Heated Vest Liner has a slim and lightweight feel. With its extremely low profile design, it will feel like a part of your body when layered under an insulated outer shell. Using Gerbing's Microwire technology and a three-panel 7V heat system (one panel in the back , two panels on the chest), you get hours of easy heat, allowing you to stay comfortable in the worst of conditions. The Gerbing Heated Vest Liner is a simple unisex garment that functions as a piece of equipment, allowing you to get the job done. The Gerbing Vest Liner is a simple garment that fits comfortably and works hard to keep you warm and enjoy cold weather like never before.
• Mobile Warming Thawdaddy 7V Battery Heated Vest - The unisex Mobile Warming Thawdaddy Heated Vest in black is a great solution if you need to place heat inside many different garments. The Thawdaddy has 3 heated panels powered by two 7.4V Lithium-ion batteries that keep you warm for hours. First, lay the vest over your neck and shoulders and fasten the front tab into place, then put your jacket on. There is an on/off button with 4 heat settings making this an irresistible piece to have for the winter. Turn any garment into a heated garment with the Thawdaddy Vest!