5/28/11 update: Summary: don't buy if you have 3x4 downspouts. Take a look at the photo I uploaded and decide if that mess is something you want on the outside of your house.
Since I'm not going to connect the second rain barrel to another downspout, I decided to attach it to the first rain barrel. There are two side connectors on each barrel, but both are male (have exposed threads.) If you're going to use the plain hose included with the barrels, you'll need
the correct quick connect.
3/18/11 Update: Smart Solar emailed a solution to me: "Buy an aluminum piece at home depot and trim it with metal cutter snippers!"
If you've never cut aluminum with snips you need to know that it makes some seriously sharp edges, so if you're going to try this I'd recommend buying a heavy pair of gloves along with the snips. You also can't cut off a section of downspout with snips, you can only cut from an edge, so you'll also need a saw to get the length you need.
In a way, I'm glad I found this out as I'm beginning to work on my garden. Now I know I need to avoid Smart Solar products.
3/17/11 Original review: I've got two of these sitting in my living room right now. They look and feel like they're well made and should work well, but until I find a way to get them installed I won't know.
The description says there's a downspout diverter, but it doesn't tell you the size. It fits on a 2x3 downspout. I've checked several homes around here, and my 3x4 downspouts are not unusual--maybe 2x3 is common where the rain barrels are made, but I can't find one here.
No problem, I'll just get a reducer. I spent yesterday afternoon driving from Lowe's to Home Depot to the hardware store--nobody had one. They can't even special order one. This morning I checked online. Reducers are apparently common for round copper downspouts, but I can't find anyone who has an rectangular aluminum (or plastic) reducer.
Amazon does have a listing for an aluminum adapter that might work. It's fifteen bucks plus ten for shipping, doesn't include measurements for both ends (so I'm not sure it's the right size,) and it's out of stock.
I called Smart Solar, hoping I'd be able to exchange the 2x3 diverters for 3x4 diverters. "Go to Lowe's and get a reducer," they told me. I explained that I'd tried that. They found me a store that sells gutters, about three hours away. No, thanks. The supervisor was asked, and said "Well, someone should have a rubber piece that would fit." Eventually I was promised that they'd email the owner of the company and get back to me.
I'll give Smart Solar a few more days to see if they want to support their products, and if they come up with a solution I'll revise my review.