Features: 1.Using a three-axis position sensor, the Al algorithm accurately recognizes and correct the wearer's posture. 2.When a bad posture of the wearer is detected, it will vibrate to remind. 3.You can freely set the angle from 5 to 50 degrees according to your age and physical condition. 4.The count of bad postures will be recorded. The Flash main control chip has a memory function, and the data will not be lost when the battery is exhausted or turn off. 5.The elastic strap adopts a movable buckle design, has strong adhesive force and super flexibility, easy to adjust and not easy to fall off, better fitting the body. Specifications: Material: ABS+PC+ Nylon Size: 110*80*15mm Weight: 80g Input: 5V/1A Charging Time: About 1.5 hours Charging Interface: MICRO USB Battery: 500mAh Packing list: 1* Unisex Back Trainer 1* USB Charger Cord 1* User Manual