Switch and thermostat box.

Here are a couple of 3104-LHTQ boxes. To this day they hold a switch and an electronic thermostat somewhere in Alberta!

Also note the odd drywall cutting work (which is mine BTW), but there's a reason for that. For fire safety reasons all the building is double-drywalled with Type X drywall sheets. In this pic the first layer is pre-installed (and caulked with fire-resistant sealant if needed) even before wiring the module. Then I would cut the drywall and install the box from the front of the wall. Further on the chain the final drywalling work is done and a 2nd layer of drywall is screwed in place.