The Sonoff T1 US is one of the cooler available smart switches in that it fits a 1, 2, or 3 circuit switch into a single gang form factor. Unfortunately, it does that by ignoring the US faceplate conventions entirely, so if you have a multi-gang junction box, the T1 simply won’t fit. I made this quick faceplate adapter to sideways-mount a T1 US in a 2-gang junction box. I actually made this plate before realizing this alternative already existed on Thingiverse, so depending on your preferred aesthetic, one may be better than the other.
Check out my version pictured above on Thingiverse also.