Where can I find the In-Wall Outlet's Serial Number?

You can find the serial number on the back of the unit and labeled SN. 

If you already had it set up on your ConnectSense app but had to perform a reset, you may still find it on your ConnectSense app, just click on any of the two outlets, you should be able to see it there.

Lastly, if you don't have access to any of the first two options, as you may already have the Outlet set up on the wall and don't feel comfortable taking it out of the wall, just take the cover off and give us a call, telling us that you missed your Serial Number and need it to set it up. 

The number on the side of the outlet represents the HomeKit Number (it is not the same as the serial number) which if you call us could help us retrieve the serial number of the device.