Intelligent Type Attentions: People with serious back problem should seek helps from a doctor or hospital. The process of correction is not easy, and you need to insist using it before you can see the effectiveness. Be sure to read the user manual carefully before use. Parameters: Charging interface: standard V8 USB interface Battery Capacity: 500mAH/3.7V Power Supply: 5V Power consumption: 0.4W Charging Time: Approximate 2 hours Charging Voltage: 5V Net Weight: 85g Material: ABS+ High elastic nylon belt Vibration description: Hold the switch for 1 second to power it on. The unit emits vibration 3 times and start the angle induction and then into standby state. Hold the switch for 1 second to power it off. The unit emits vibration 3 times to power off. Common problin use: If the posture reminder is not sensitive, pls try to tighten the strap, and at the same time, the back should be straight at the time of powered on, and the chest should be deployed as far as possible. If the posture reminder is too sensitive, pls try to loosen the strap. If you encounter abnormal vibrations, pls sit upright, then reboot the reminder. 3 If the reminder can not be switched on, pls charge the posture reminder for 10 minutes, and if there is no reaction, contact us for after-sale service. Packing list: 1 x Intelligent posture reminde