The USG is a versatile hardware USB firewall that segregates a potentially harmful device from your PC. USG1.0 supports mass storage (flash drives), keyboards, and mouse. It can protect USB devices when connecting to unfamiliar computers and protect our computer when connecting with unfamiliar USB devices. With USG, a Strong web-application firewall such as Incapsula CDN identifies the malicious threats using several layers of security policies. You can build your own USG with instructions. The maximum speed of transfer will be around 1MB per sec.”]
Source: https://gbhackers.com/usg-hardware-firewall-usb-ports/