?Customer Service?I always adhere to the principle of customer first, and I sincerely hope that every customer can feel satisfied with our service. If you have any questions, I also hope you can contact me at any time, and I will be ready to answer any questions you may have. Thank you for liking my products. ?Gift Package?In addition, we will give you a box to take with you and different sizes of earbuds for you to change. Adjusting the volume is done by simply turning the rotary button. ?Smart Noise Cancellation?With digital chip technology to help automatically suppress noise distortion. ?Rechargeable? The machine is fully charged for about 2 to 4 hours and can be used for about 80 hours. Keep it in a small case, easy to carry and go out. (Tip: This is USB rechargeable, no need to replace the battery often). ?Adjustable Mode?You can choose from 3 different frequency modes and 4 volume levels to ensure that you can fit in different volume environments. Comfortable size, easy to wear anywhere and anytime.