TP-Link UB400 is a Bluetooth 4.0 Nano USB Adapter designed to add Bluetooth functionality to computers and laptops that lack it. It utilizes Bluetooth 4.0 with Low Energy (BLE) technology and is backward compatible with older Bluetooth versions. The adapter is plug and play for Windows 8 and above, meaning it doesn't require a separate driver installation. It's a small, nano-sized device for convenient portability and is compatible with Windows 11/10/8.1/8/7/XP.