Posture correction device that uses vibrations to alert you to correct your posture when you lean forward. Includes the instruction manual, USB charging cable, and anti-slip knot that came with the purchase. I bought this to improve my straight neck and used it several times, but I no longer use it because my symptoms have improved, so I am selling it. It vibrates when you actually lean forward. I was conscious of improving my posture before the vibration occurred when I was wearing it, so I rarely noticed the vibration, but I think my posture improved while wearing it. Shoulder stiffness relief, distortion prevention, adjustment function, kyphosis correction, posture corrector