No, the surge protector is grounded so it only fits one way. If you plug it into the top of a duplex outlet it covers the bottom. If you plug it into the bottom, the top outlet remains accessible but not there is not enough room for something as large as another surge protector.
You can't plug two of them into the same outlet. But there is no reason to do that because of how these devices work other than allowing for more energy to be absorbed. If you think you need more than 900 joules get a device with a higher rating.
Got three of them and they fit just perfect where I needed them. Like the way it lights up that shows my treadmill, microwave and refrigerator are protected. Great products and will definitely buy from Monoprice again.
If You Need a One-Outlet Surge Protector, This Is It
I wanted a one-outlet surge protector, and this fills the bill nicely. The price makes it a good value, too. And I like the visual/audible warning that the device has taken a hit and failed (and should be replaced). All in all, I’m pleased and will order more.