Venture Heat Women's Heated Base Layer with Battery 6Hr - The Nomad 1/4 Zip Shirt, Carbon Fiber TRI-ZONE CARBON FIBER: Our exclusive Z-Stretch XCT carbon fiber heating element features 3 built-in battery powered heating panels to boost your core body heat. This ultra thin and efficient infrared heating system ensures smooth comfort and quick warmth to your lumbar, shoulders, and abdominal region. 6 HOUR RUNTIME - Includes a slim 5V 5000 mAh CE certified battery (which doubles as a phone charger!). Adjust temperature to your heat panel with an embedded heat control button. Batteries operate up to 6 hours on low, 4 hr (med), 2 hr (low). RECHARGEABLE: Our heated clothing is activewear / workwear designed for extended reuse in cold weather. Excellent layered under a jacket or as an undershirt for outdoors, ski, snowboarding, hunting, fishing, cycling, biking, camping, or the general cold weather freeze. STRETCHABLE HEATING: Our antibacterial, moisture wicking, lightweight synthetic fabric is integrated with uniquely designed stretch heat elements to move and flex as you do. Waterproof quarter zip YKK zipper. MACHINE WASHABLE: Machine wash gentle cycle in warm water. Dryer safe. Includes zippered travel pouch. Designed in California. 12 month covered warranty. Includes the Venture Heat overheat safety feature.