The SEL CP210x USB to UART Bridge is a driver for a USB-to-serial communication chip made by Silicon Labs. The CP210x series of chips are commonly used in applications that need to convert data from USB to UART (Universal Asynchronous Receiver-Transmitter), a common interface used by many serial devices such as microcontrollers, sensors, and other embedded systems.
If you're using a device that connects via USB and is based on the CP210x chip, you will need to install the CP210x USB to UART Bridge VCP Driver in order for your Windows PC to communicate with the device properly.