Portable Rechargeable Charging Dock As a power bank, this portable charging dock can hold 450mAh electricity. When the charging case is fully charged with a micro USB cable, it can provide 3-4 times quick full charge for twins earbuds without USB cable. With 40mAh battery capacity per earbud, the working time of this bluetooth headphones is "one earbud for 3-4 hours, and a set for 2-3 hours". Note: After the earbuds are fully charged, please slide the switch to "OFF" to save energy for next charge. Share Mode: After successfully pairing with each other, you can use this twins bluetooth headphones together. When using with this mode, you can share music or video with your lover at the same time, both of you will enjoy high quality stereo sound listening time. Single Mode: Each of the twins earbuds can be used for single channel mode, it supports all functions in additional to listening music with share mode, and skipping to next song. When using with this mode, you just only need to buy one set, send one to your lover/family/friend, keep the other one for your own use, both of you can enjoy wireless listening time. [Package Included] 1 set of Bluetooth Earbuds(left & right); 3 x Spare Ear Tips( L/M/S); 1 x Ear Hooks; 1 x Micro USB Charge Cable; 1x 450 mAh Charging Box; 1 x User Manual.