4x extended USB ports, switchable two inputs, sharing USB devices for two hosts Industrial grade HUB chip, adopting MTT technology, allows stable and smooth 4x concurrent USB connections ESD protection for each USB port, preventing electric surge damage and data loss. Over-voltage protection, effectively preventing other high voltage power input from damaging the connected devices Multiple protection circuits: over-voltage, over-current, short circuit, over-temperature, reverse current, under voltage lock-out, 8KV ESD protection, filtering protection, etc. Industrial grade metal case, rugged & durable, with mounting holes for easy installation