The most rugged USB Hub on the Market!Our Industrial Grade USB Hubs are designed for the harshest environments. They are EMC tested to meet heavy industrial standards. The four port hubs are UL listed for Class 1 Division 2 hazardous locations. High retention USB connectors hold standard USB cables tight and are perfect for high vibration applications. The UHR304 and UHR307 offer 4 kV Isolation between the upstream and downstream USB ports to protect expensive equipment from dangerous ground loops and to help ensure data integrity. No doubt about it, these hubs will operate where standard office grade hubs fail - such as near variable frequency drives, motor control centers, welding, and other large electrical loads.