INTELLIGENT POSTURE REMINDER: The correction has the latest inductive design. When the user's back is bent more than 25 degrees, the back reminder will automatically sense and immediately activate the vibration alarm; When your shoulder is bent forward and the tension is abnormal, the sensor will immediately vibrate to remind. LONG STANDBY TIME: back corrector uses a 500mAh polymer lithium battery and can be used for about 15 days after 2 hours charging, it is easy to charge by connecting USB cable. Switch has indicator light, constant red light means normal charging, constant blue light means full charged / normal working. If you can't turn on the reminder, please charge it for 10 minutes first. HIGH-ELASTIC NYLON BELT: The high-elastic nylon shoulder strap is easy to adjust,it is better elasticity and more comfort, which is suitable for people from 15 kg to 95 kg. The shoulder strap is made of porous mesh, which is breathability without sultry. Won't dig into your armpits, hurt your skin, it is comfortable and provides all day wearability. SCIENTIFIC AND EFFICIENT CORRECTION: We recommend that users wear the posture corrector for 2 hours per day. 21 days is the period of habit formation, and posture will be significantly improved, 90 days of persistence will enter the period of habit stability. The correction process is not easy, this corrector is great choose for promoting a long term muscle memory. If the corrector does not vibrate accurately, please read USE TIPS below. is an excellent Amazon brand seller, providing 24-hour customer service, so you can rest assured after purchase. If you have any questions or dissatisfaction, please feel free to contact us. We are always here. Battery capacity: 500mAH / 3.7V Power supply: 5V Power consumption: 0.4 W. Charging time: about 2 hours Charging voltage: 5V Net weight: 85 g Material: ABS and elastic nylon belt Charging interface: standard V8 USB interface