long Battery Life- M20 Bluetooth Earpiece Built-in 220mah Rechargeable Polymer Lithium Battery, Provides 8-10 Hours Music Play/call On A Single Charge. And The Earphone Is Fast Charged Fully In 1.5 Hours.easy Operation- Long Press The Power Button For 3s To Turn On/off, Once Click To Play/pause/answer/hang Up, Long Press For 2s To Reject Call, Double Click To Redail The Last Call; Click Once The "+"/"-" To Switch Previous/next Song, Long Press The "+"/"-" To Adjust Volume.left/right Ear Wearing- The Bluetooth Earbud Can Be 180° Rotated, Fit For Both Left And Right Ear Wearing, The Earhook Design And Tpe Soft Material Make No Pain To The Ears, Suitable For Long-time Wearing, Such As Sleeping, Walking And Working Etc. Ipx5 Waterproof/sweatproof Withstands Sweaty Exercise In The Gym.universal Compatibility- The Bluetooth Headphone Is Compatible With Most Bluetooth Enabled Devices, Including Cell Phones, Tablets, And Laptops. It Can Also Connect To 2 Devices At The Same Time. (zhongchengdaye)