Outer: 100% Polyester | Outer: 100% Polyester .Lightweight and FlexibleMoisture-Wicking, Copper infused to reduce odors | Great For Men and Women. Quickly and Easily Correct Posture – Properly Align Your Neck, Shoulders and Spine | Reduce Neck, Back and Shoulder Pain – Relieve stress from supporting neck muscles that may induce neck pain and decrease mobility. And aid shoulder and back pain that can be caused by long periods of sitting or lifting | Sizing Information - The Posture Support Fits a 33"- 44" Chest. Please refer to the video for sizing and adjustment instructions. | Promote Postural Awareness - Continual wear of the posture corrector instills a reminder in your body to maintain proper posture. This will improve function and decrease pain leading to overall better posture.