Machine washable KEEP YOUR BODY AND HANDS WARM: Qualified carbon fiber heating elements with 3 heating levels(approximately 149F, 131F \u0026 113F) to generate consistent heat for 4 core body parts, including your neck, back, abdomen, and waist, helping to maintain body warmth, promote blood circulation, and relieve pain as well as tension in muscles. NEAT and TAILORED DESIGN: Lightweight insulated for you to wear in many ways with unrestricted movement; Water and wind-resistant. Sharp fit design will be perfect for wearing underneath your winter jacket. LONG-LASTING USAGE: A 10000mAh power bank offers up to 8 to 10 hours of warmth on average(lasting period can be vary depending on different types of power bank); Power bank is NOT included in our product.The AYS team is at your service and we hope you enjoy your life