This is a dongle that can be used to substitute the need for a wired Xbox 360 controller when performing authentication for stock Xbox 360 consoles. The dongle itself is very small, and can be left plugged into the USB-A port on the top of the V3 adapter, or the Controller Authentication cable in a kitted guitar. This provides a plug and play experience on 360 and is ideal for players who use that console often. The dongle can also be left in while playing on PC and non-Xbox consoles, as the adapter/guitar will detect the console and disregard the need for the dongle. The only time you would need to disconnect the dongle would be if you specifically wanted to play Rock Band 4 on Xbox Series/One, as that would require authentication with a controller from the generation of Xbox. I personally use one of these on my main modded guitar; the fact I can plug it into my 360 without even needing to think about auth is worth every penny!