When traveling I tend not to bring my laptop but only my phone, sometimes iPad as well. I don't have a whole stack of SD cards so I need to copy the data from the SD cards over to a HDD. For my last trip I had bought a RavPower filehub jobby. It has a SD card slot, USB for external HDD, WiFi and an iPhone app, seemed brilliant on paper. - It didn't work the way I was hoping... It did technically work, but at the end of a day I needed to copy some 100GB of footage over to the HDD I realized the limitation of the device - Dog Slow! 'The system' required the iPhone app to be in the foreground the whole time. The little device would run out of power even though plugged in to USB. It was using more power than it could take charge. So for a few MB it would be fine but.... So I'm looking for a new 'device' of sorts. Something that will allow me to copy data from SD cards over to USB HDDs reasonably fast. Any recommendations? Or any devices I should steer clear of?