Charging function We provide a USB charger to save you the trouble of buying batteries. The device can be easily turned on/off using the power switch. The volume can be easily adjusted by just touching the button without any tools. And he can be charged anywhere there is a USB socket, such as company computers, home sockets, etc.Lasts all day: Time to upgrade your and forget about always running out or changing batteries. Now the Energy efficient rechargeable batteries gives you longer battery life and use between charges. Without changing batteries all the time you will be free to do the things you loveCharging BoxMachines can be fully charged within 2-3h and can reach an ultra-long standby time of 35-48h after being fully charged. With the current smaller appearance as well as the small charging case, meet your convenience to carry as well as invisible wear, use anywhere, anytime.Customised design - Weighing only 3 grams individually, it is easy to wear. Easy and comfortable to wear. Comes with different sized earplugs to perfectly fit each individual ear.Customer ServiceIf 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.