Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Can I add 2 of these devices to end up with 4 extra monitors to my laptop?
Document: I was hoping to add external graphics processing with this device, supplementing the native low-end graphics capability of the notebook. But the 'Plugable' turned out to be a passive device.Using the VGA connector, it manged to display static JPEG images after a long pause on the UXGA monitor.
Works great with my laptop to expand to 3 monitors. Running full HD with it plugged into USB 3.0 hub from the same brand. Event the Ethernet works perfectly.The best part about this setup is that after getting a new laptop that doesn't work with my docking station anymore, I now have to only connect 2 cables (power and the USB 3.0 Hub) and everything is connected.Couldn't be easier.
I don't have anything massively graphically taxing to try on this laptop, so it was just Youtube and Lotus Notes on each of the 2 screens. Performance was passable and worked OK. I only drove one screen in this mode, so adding 2 screens and also using the wired ethernet might not work so well over USB 2.Overall, if you have a need for more monitors on a device and don't have the option of putting another video card into the machine, the Plugable Dual Head is perfect.
I have a Lenovo Carbon X1 which has a mini display port, no Ethernet, and 2 usb ports (1 of which is usb 3.0). I bought this adapter so I could hook up two external monitors (3 total including laptop monitor) and use Ethernet (wifi at work is dodgy at best). I'm very happy to report that this device works perfectly. I have 2 external monitors going (1 DVI, 1 HDMI) and Ethernet with no issues.
I bought this to plug in a second screen to my laptop, which only has 1 monitor output. It works, but I have 3 complaints:1. Ever since I started plugging in this thing using two screens my screen has started flashing unexpectedly, drawing lines etc.2. When the screen goes to sleep, on wake-up both external monitors go berserk flashing until I unplug the VGA screen.3. The cursor movements etc in the screen connected via this device are way too choppy.
I love having 3 monitors. Quick response times. Great for work or play. If you have USB 3.0, and an extra monitor or two look into the Plugable product line.
I then began searching for a solution and found that Windows 8 supports taskbars on multiple displays. When I went to enable the option, I found that the option was completely missing from the properties window (as if I only had a single display).My laptop has an extremely high resolution, nearly 4k (Yoga 2 Pro), which ended up being the source of the problem I encountered.
If you are a laptop user (or even desktop user) who wants flexibility on how they connect additional displays, this is a great option. My laptop came with just 2 USB3.0 ports and is too thin to include a native GbE port, so I wanted to maximize the use of those ports (I always like to have one free for someone to hand me a USB drive or whatever else comes up).
After getting the driver installed (easy as long as you are not locked out of administrator rights) this thing works like a champ! I have 2 portrait oriented monitors for long email strings and calendar, and 2 big main monitors for working online. HIGHLY RECOMMENDED!
I would have given this 5 stars except for 2 very minor things:1. It's a little bit bulky. It's not too bad but for those with limited desk space, it doesn't look very good2. The cord is a bit short.Other than those 2 things, it was a fantastic buy. It comes with a little vga adapter so if you dont have hdmi or dvi it can still be beneficial. You can run multiple monitors simultaneously with this as well.
Answer: I have seen plugable videos where utilizing a USB 3.0 hub the owner of plugable uses several of the single adapters to have 7 monitors off of one computer. I wouldn't think this is any different.https://www.youtube.com/watch?v=pYUdAWOGJ_Y