Feature:1. Convenient Charging: You can charge your phone no matter where you are, no more limitation from fixed power source. Suitable for 21700 battery, also compatible with 18650/18700/20700 batteries2. Single Battery Available: The inner battery box can contain 2 batteries, but only 1 battery loaded can make the power bank work, providing a satisfying using experience.3. Protection Function: Built in chip has overvoltage and overcurrent protection, taking full care of the safety of your mobile phone and battery.4. Portable Type: When traveling, you can carry the DIY power bank in your pocket, bag, briefcase or suitcase to mobile phone charging at any time.5. Wide Application: Suitable for mobile phones, and can also be used for MP3, MP4, digital camera, tablet computer and other products by different cables. DC 5V universal power supply.Specification:Item Type: DIY Power BankMaterial: ABSModel: H02BApplication: For Mobile PhoneBattery Type: 21700 Battery x 2(Not Included); Also Compatible With 18650/18700/20700 Batteries (Not Included)Weight: Approx. 69g / 2.4ozOutput Port: USB 5V 2AInput Port: Micro/Type-C 5V 2AScope Of Application: Support All Types Of Mobile Phone Charging.Package List:1 x DIY Power Bank CaseNote:It's just an empty shell, can be used as a power bank after batteries are plugged.