Others might have some more knowledgable input...but here's my $0.02.
Usually, multiple drive enclosures provide some sort of RAID...I don't see anything mentioned on the product page.
If you have 2 * 500GB drives, do you get a total of 1GB storage? The RAID # will tell you this.
I'm also wondering why there are two eSATA ports. The blurb seems to indicate one for Mac one for PC...but then, why is there only 1 USB port?
I'd recommend a bit more research to make sure this is the right kind of enclosure.
Plus, it's made in China...so make sure you (and your kids) don't lick it.
I found this
Newegg.com - Thecus N2050UD Up to 1 TB Direct Attached Storage USB 2.0, eSATA - Retail, it seems closer to what you'd need...though I'm unclear why it indicates a max capacity of 1TB. (I'm not recommending this as I have no experience with it, but it does appear to have the features you'd need/want and be pretty cheap.)