The Latest Model for 2019 is equipped with One-Step matching and automatic Power-On and Power-Off technology. Once you take the Earbuds out of the charging case, it will turn on and pair with each other automatically. When put in the charging case, it will automatically turn off and stay on charging until fully charged.
A Mini Portable Power Bank charging case with built-in 400mAH battery. Make Sure the Earbuds A

are charged reliably. Earbuds fully charged gives 5-7 Hours continuous music playtime. A total of 90 hours is available. So you don’t have to worry about charging when you go out. You can also use the charging case to charge your smartphone when phone is out of power.