Dear Friends,If you need 4XL size, you can order 3XL size and leave a message "you need 4XL size", or contact with our customer service, thanks!) Tips: This product is not include with a power bank Men Size Recommend : Height: 155-160cm, Weight: 40-50kg, Recommend Size: S Height: 160-165cm, Weight: 50-60kg, Recommend Size: M Height: 165-170cm, Weight: 60-70kg, Recommend Size: L Height: 170-180cm, Weight: 70-80kg, Recommend Size: XL Height: 180-185cm, Weight: 80-90kg, Recommend Size: 2XL Women Size Recommend : Height: 150-150cm, Weight: 45-50kg, Recommend Size: S Height: 155-160cm, Weight: 50-57.5kg, Recommend Size: M Height: 160-165cm, Weight: 57.5-62.5kg, Recommend Size: L Height: 165-170cm, Weight: 62.5-67.5kg, Recommend Size: XL Height: 170-175cm, Weight: 67.5-72.5kg, Recommend Size: 2XL Features: Intelligent temperature control, heated with knees, back and waist. Powered by any 5V / 2A USB portable charger, the USB plug is compatible with most portable chargers on the market. Which can start heating in 30 seconds, long duration and long heating time. 3-level adjustable temperature with indicator light to adjust the required temperature. Safety insulation design, built-in thermal protection module, 5V safety voltage, once overheated, it will stop running until the heat returns to the standard temperature. Support manual/machine washing.The safety protection function ensures that the machine is not damaged during washing. Heating underwear helps to improve blood circulation, enhance metabolism, which is very suitable for people who are afraid of cold, Raynaud's disease, arthritis, poor blood circulation, and stiff joints. The best solution for various outdoor activities, such as skiing, fishing, jogging, Hunting, biking, hiking motorcycles, protecting climbing dogs, Running, snow removal, etc. Specifications: Name: Heated Thermal Underwear Condition: Brand New Color: Black, purple Gender: Men, Women Material: 91.1% Polyester + 8.9% Spandex, Carbon fiber wire Heating temperature: Red LED 50, White 45, Bule LED 35 Power supply: USB power bank (Not include, 10000mah power bank can be heated for about 5-7 hours) Size: S, M, L, XL, 2XL Season: Autumn, winter Package includes: 1 x Heated Thermal Underwear Tops 1 x Heated Thermal Underwear Pants (Note: Not included power bank) How to use : Charging - Fully charge the power bank, before use. Plug-in type-connects the power bank to a plug located in the pocket. On-Press and hold the on / off button for three seconds. The initial temperature is 50 degrees (red LED), the intermediate temperature is 45degrees (white LED), and the lowest 35 degrees (blue LED). Cleaning and maintenance : Machine washable. When washing, remove the power bank. In the case of machine washing, please wash your clothes in a laundry bag. To ensure the longevity of clothes, try to avoid strong washing and normal drying.