20 Hrs*4 of Continuous Warmth: 3 heating levels can be selected with a simple button. Heats up to 130°F in just 2 seconds. The 3000mAh*4 capacity battery can last up to 20 Hours *4 of warmth
More Practical Design: Double the heating area, especially suitable for the hyperthermia needs of patients with Raynaud's arthritis. The ergonomic design can be held perfectly in your hand and easy to carry to anywhere. Perfect for outdoor sports, camping, hunting, hiking, golf

Comfortable and Compact Design: AaoLin hand warmers feature a compact design that is only 0.7 inches thick and less than half the length and weight of a cell phone. Fitting easily into gloves, pockets, or purses, It is the perfect companion when fighting the cold.