Fabric: 90% polyester + 10% spandex (milk silk) Thickness: Level 4. It won't fade when soaked in warm water with laundry detergent for 24 hours. The milk silk fabric is light and soft; the cross-section of the fabric is full of grooves. This allows sweat and moisture to diffuse and evaporate quickly, keeping the body dry. Spandex makes the clothes highly elastic and tight-fitting, reducing energy loss caused by muscle vibration, promoting blood circulation, and relieving muscle fatigue.