This adapter has female 5.5 x 2.1 mm DC barrel jack on one end and a regular male micro-B USB plug on the other end at 90 degrees angle.

It is handy if you have 5V DC power supply with a barrel plug and you want to power a micro-B USB device.

Take note that this adapter does not do any voltage conversion. Most, if not all USB powered devices runs on 5V, be mindful of the voltage that you connect to the barrel jack.

Do not connect anything more than 5V to your USB devices!