The ZD1211 IEEE 802.11bg USB Adapter is a wireless network adapter that allows a computer to connect to Wi-Fi networks. It supports the IEEE 802.11b and 802.11g standards, providing wireless connectivity for data transfer over Wi-Fi. The ZD1211 refers to the chipset used in the adapter, typically manufactured by ZyDAS (a wireless chip company). This USB adapter is often used to add wireless networking capability to desktops or laptops that do not have built-in Wi-Fi.