The Pantech USB Modem Composite Device is a driver for devices that use a Pantech USB modem to connect to a mobile network or the internet. These modems are typically used for 3G/4G data connections and are often found in USB dongles or mobile hotspots. The Composite Device refers to the fact that the modem might have multiple functions (such as a storage device and a modem) that are accessible through the USB connection.