1.Scientific Design - The posture trainer has two detachable fiberglass ribbons with strong toughness and plasticity. It can provide strong stability support and maintain the physiological curve of normal human spine to achieve improved posture in a short period of time. The back and shoulders become more upright, while neck, shoulder and back pain is relieved.^2.Protective design - Advanced breathable environmental protection material, which is not easily deformed by elastic force. At the same time, it is equipped with two soft pillows to effectively protect the shoulders and forearms from injuries.^Use 3 - Posture Correction is similar to a backpack. First the shoulder is fixed and then the stomach. Finally, the comfortable shoulder strap is adjusted. It can be easily carried and adjusted without tools and the body is held in a straight posture. High quality, breathable, soft material ensures long wearing comfort.^4.Adjustable size - The back posture corrector is designed with high elasticity. The size of the back, shoulder and waist can be adjusted by yourself. It is suitable for all men and women with a chest of 80-110cm. You can adjust the comfort size to suit your needs.sizeS: Back length: 28cm Waist: 80cm Shoulder strap length: 90cm (65)M: Back length: 30cm Waist: 95cm Shoulder strap length: 95cm (70)L: Back length: 32cm Waist: 110cm Shoulder strap length: 110cm (80)XL: Back length: 33cm Waist: 130cmShoulder strap length: 120cm (90)