The TP-Link UB400 is a compact Bluetooth 4.0 Nano USB adapter designed to add wireless connectivity to your desktop or laptop. By plugging this small device into a USB port, you can connect up to seven different peripherals simultaneously, such as wireless headphones, mice, or keyboards, within a range of 10 meters. Its tiny dimensions of 14.8 x 6.8 x 18.9 mm allow it to stay discreetly in your port without blocking adjacent slots, making it an ideal choice for those who move their laptops between locations frequently. The adapter utilizes Low Energy (BLE) technology and maintains backward compatibility with versions 3.0, 2.1, 2.0, and 1.1 to ensure it works with a wide variety of older gadgets. Setting up the device is straightforward on Windows 8, 8.1, 10, and 11 thanks to its plug-and-play functionality, while users of Windows 7 or XP will need to install a driver. This black adapter is built to operate in environments ranging from 0°C to 40°C and carries FCC, CE, and RoHS certifications for safety and quality standards.