Features:-The volume can be easily adjusted with just a screw turn-Built-in energy-saving rechargeable battery prolongs battery life and extends the time between charges, supporting all-day use.-The charging box can be fully charged in 1.5 hours, and after being fully charged, it can achieve an ultra-long standby time of 35-48 hours.-Each weighs only 3 grams, which is convenient and comfortable to wear. It comes with earplugs of different sizes to fit everyone's ears perfectly.-It adopts a compact and lightweight design, which satisfies your convenience of carrying and invisible wearing, and can be used anytime and anywhere.Specification:Colour: black&red&blueStyle: in the earPower source: built-in 300mAh batteryEquivalent input noise: 23dB &plus.