Thank you for viewing. This is an Alpine remote control receiver. I believe it was for a digital terrestrial tuner or DVD player. It's from a few years ago and has been stored in a warehouse for a while. For those who can tell from the images, how about it? It was working fine until it was removed, but I can't confirm it now, so I'm selling it as junk. The plug size is, according to my amateur measurement, 2.5mm. Please judge the condition from the images. Please refrain from purchasing if you are looking for a perfect new item or are overly sensitive, to avoid any problems. Shipping is free. Please understand the above and consider purchasing if you understand that this is a used item.