This is a Realtek RTL8761 Bluetooth 5.0 adapter. I am selling it because I purchased a new Bluetooth adapter. I was using it without any problems until recently, mainly for connecting wireless earphones and a mouse. The usage environment was Windows 10 and 11. (Generally, you should be able to use it just by plugging in the adapter, but you may need to configure drivers depending on your PC.) Bluetooth 5.0 is not the latest standard, but it is still used in many devices and is a standard that can be used without problems for everyday use. Please purchase with the understanding that this is a used item. It will be shipped in an envelope, so it will likely be delivered to your mailbox. Free shipping, immediate purchase welcome.