USB On-The-Go is a really useful USB specification! It allows some small devices that would usually be unable to act as a host to have limited hosting capabilities! USB-OTG is common for things like tablet computers and smartphones in order to allow for USB peripherals like flash-drives, keyboards, etc. to be hooked up.

If you have a USB OTG device, you need one of these Female A to Micro-A cables to act as a host. Remember, not all devices are USB-OTG compatible, so make sure that whatever you're plugging in actually has this ability so you don't damage something!

Note: Most tablets and mobile phones have Micro 'B' connectors which is keyed differently than the Micro 'A' on this cable and will not fit! Remember to double check that your device features a Micro 'A' connector to ensure compliance with this adapter.