ShouldersBack was designed by a leading team of orthopedic specialists. Its cool, comfortable, all-elastic design allows full range of motion while gently reminding the user to maintain good posture. By keeping shoulders retracted and the spine in proper alignment, ShouldersBack reinforces and helps maintain correct shoulder positioning, enabling the wearer to maintain perfect posture. Wearing it for as little as an hour a day will aid in retraining muscles to maintain good posture and promote better health. Help create an overall sense of wellbeing and optimize your daily work performance with ShouldersBack! Sizing: Measure circumference of rib cage. Small fits to 24", Medium fits up to 38", Large fits up to 50". Small is equivalent to youth sizes.