I plug in a USB 2 Key External Hard Drive 500gb an SD card and a micro-SD at the same time and without any problems (on a Nexus 7, 2013)! The small USB power cable supplied with is very convenient to feed when you plug a hard drive. It faudras you root your Nexus 7 Install StickMount and move SELinux to permissive mode, that in 10 minutes if you have the necessary knowledge, but if we do not have them, drop, it is best to do! There are other applications that do not require all these knowledges, but it is less convenient for my taste, and often paying. However, the micro-SD port starts messing but still works for now. A RECOMMENDED!