Features： 1、8 Shape brace stretch, open shoulder straight back, adjustable shoulder strap, stable stretching force. 2、Helps correct poor postural habits and ease neck, back and shoulder pain,easy and convenient to use. 3、Allows you to actively adjust the correct posture through vibration prompts without being restricted by traditional correction bands. 4、There are three magnets on the back, which can stimulate the acupoints to relieve discomfort and correct the back posture. 5、Vibrate to remind design, more effective to improve self?awareness of back straightening, especially suitable for sedentary people and students homework time. Specification： Item Type: Posture Corrector Material: SBR+ Polyurethane +PU Magnet Battery: Built-in lithium battery 500MAH Wear steps: 1. Adjust the straps to a suitable length and wear them well 2. Press the power-on indicator light in the center of the back 3. Maintain the correct posture, reminder will record the correct posture 4. The correction belt will vibrate to remind when there is bad posture Wear two hours a day, develop the habit of straightening back Size ShoulderWeight S 26-36cm / 10.2-14.2in15-40kg M35-45cm / 13.8-17.7in40-70kg L42-48cm / 16.5-18.9in70-95kg Package List： 1 x Posture Corrector 1 x Charging Cable