USB Port Blockers are useful little devices that system administrators can use to physically prevent access to USB ports. USB Port Blockers allow locks to be inserted and removed from USB ports to stop unauthorized users from inserting pen drives, USB mass storage and mobile devices into shared workstations or devices with USB ports in public spaces.To use, simply attach a lock to the key and insert it into the USB port. Release the sliding mechanism on the key to leave the lock in place. To remove, simply insert the key back into the lock and pull away.