The Micro-B plug is for OTG device and also for Power charging. Can connect your device to most USB Flash Drive, Mouse, Keyboard and etc. 

Compatible with :Samsung Galaxy S2/SII/i9100, Nokia N810 N9, Asus Google Nexus 7/10 and any other Micro USB devices with USB Host Mode Support.

 Works with USB memory stick, USB memory card reader ,keyboard or a mouse. 

Also it works with external hard disk, but you need the external power source for the hard disk. 

Please make sure your phone/tablet support OTG ( On-the-Go ) Please check the compatibility of your phone/tablet before purchasing.

 Color: black Female end Compatible with : USB 1.1 and 2.0 Compatible

 Package included: 1 x Right Angle Micro USB Adapter