Cooling and Heating 2-in1 Design - It heats in 3s and warms your neck quickly, warm up to 45℃; it is also a powerful cooling fan for providing you cool breeze down to 15℃ 8 Working Modes - Easily adjust the suitable one mode to fit you  Comfortable Neck Hanging Design - Putting less strain on the neck, no harm to your body LED Display Screen - Built in a digital screen to show the temperature USB Rechargeable - Compatible with most USB output devices, such as power bank, adapter, car charger, laptop, computer, etc Low Noise - This fan will keep you cool while working and is super silent around your neck so that it doesn't disturb you with noise Specification: Battery capacity: 2800mAh (KC certification) Product size: 164*153*54mm Input: 5V/2A Product material: environmentally friendly ABS + environmentally friendly silicone + environmentally friendly aluminum Rated power: 4W Battery life: about 3 hours Cooling mode levels: 25℃, 21℃, 18℃, 15℃ Heating mode levels: 38℃, 40℃, 42℃, 45℃