My family purchased this, but I'm selling it because I don't use it. 1. Vibration: The back straightener uses gentle vibrations to remind you to maintain a healthy posture and keep your back straight. 2. Prevents Kyphosis: The back posture corrector ensures comfort for the neck and shoulders, effectively preventing slouching and forward shoulders. 3. Keeps You Straight: The back straightener can promote long-term muscle memory, so you'll stand straight even when you take it off. 4. Wear Directly: You can comfortably wear the upper back corrector directly on your back without removing or adjusting the shoulder straps. 5. Excellent Material: A smart back corrector made of abdominal muscle material. It's firm and durable, easy and comfortable to wear without breaking. Specifications: Item Type: Vibration Back Straightener Material: ABS Battery: Lithium Battery (Included) Capacity: 800mAh