Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: Does this require an ADD-ON to put inside your computer? How does the USB 3.0 fair? Any problems?
Document: This is just about the worst piece of equipment I have ever ordered from Amazon.It is noisy and the connect for eSata didn't work at all. The box shut down. In addition, I put 2 hard drives in and while both showed up on my computer, no lights indicated either. The only way I could connect is with the USB 3.0 cable. That is a problem itself. The cable is incredibly short and has a non-standard connection to the unit.
WOW!!! How to write this review????? First...THE GOOD....It works as it should. You can put up to 8 SATA drives in and connect to a computer via USB 2 or 3...OR...E-SATA.
I bought this as an upgrade to an older USB 2.0 four bay model. The 3.0 interface works for me and has doubled my speed. I have seven drives loaded and no problems. yet.
It appears that all of these external multi bay hard drives are junk.-----My set-up: Windows 8.1 and an Intel DH67CF motherboard, running off of the internal USB 3.0.I've had endless issues finding a  multi-bay drive enclosure which is rock solid. I went through a few Sans Digital units over the years, all caused me endless problems.
I have 8 drives in it using WHS 2011 and Stablebit Drivepool. I've had so many problems with this box but I can't blame all of it on it. I tried USB 3.0 but it's so finicky. It's slow and disconnects the box during high workloads. esata is the way to go. I purchased 3 x Sil3132 cards but they all had the same issues. It disconnects during really high loads. I looked through their support site and realized that Mediasonic sold an esata card that compatible with this unit.
First let me say that I own 2 4-bay Mediasonic Proboxes and love them more than any other computer component other than my 6 core AMD Shuttle computer. So when I was looking into buying a third 4-bay box Amazon suggested, as they always so insightfully and accurately do, the 8-bay tower.I connect my Proboxes with eSata not USB 3.0 because USB 3.0 is inferior to eSata in data transfer speed, period.
After I received this device, I could not get the device or my computer to recognize the hard drives. After 3 hours of fiddling and research, found out the top 4 bays didn't work. The instructions say to install drives from top bay down, but you can put the hard drive in any bay and the device should recognize the drive.
I am probably gonna keep the bottom bay empty for better air flow and use it as a safe, I mean who is gonna look for money in a computer geek's hard drive tower, right?But if you are most people, and most of you reading this are, you will be using USB 2.0 and not care about speed of data transfer.
I have the four bay and the eight bay ProBox units. The four bay works great, but the eight bay keeps prompting me to format the drives which are already formatted and contain important data. These drives work great inside the computer case or other enclosures, but just aren't recognized in the eight bay unit. I've tried on two seperate pc's and have also tried with esata and USB 2 hookups, but same result.
I can hold 3 TB Hard Drives......8 of them. What else can you say? It does what I expected it to do. I am using the USB 3 connection and it is fast and I have not had any problems for almost a year now.
Answer: There are no ADD-ONS required.  It uses USB and ESATA interface which plugs directly into your motherboard.  I have three of these.  I bought one in 2011, 2012, and 2013.  My original Probox ( 2011 ) works just as good as the one I bought in 2013.  The ones I got in 2011 & 2012, are continuously running 24 hours a day and uses the USB 3.0 interface.  The one I bought in 2013 is being turned on and off constantly with no problems or loss of hard drives and it too uses the USB 3.0 interface.  I have used a combination of hard drive with various sizes and manufactures.   Now I am using mostly WD red label NAS drives  All three of my Probox cases have WD 2tb drives.  I am using WD red, and green label drives.  I am slowly phasing out the green label drives with the red label NAS drives because they are designed for servers.  I had two WD black label 7200 rpm drive in the cases but I had to remove them because they were getting to hot.   To sum it up the USB interface for me seem to be adequate for running all my drives.  I even run all my games from one of the Proboxes without any problems of continuous loading and accessing of the drives.  One of my cases has all my movies and is plugged directly into my router as a server and have not had any problems so far.I hope this will help.