Low voltage mounting ring can be used for class 2 circuits such as the switches used in the stair lighting controllers. To install you will need to cut a rectangular hole into the drywall. The plastic ring is inserted into the hole and when the upper and lower screws are turned to secure it in place the two wings move into position where they hold the low voltage mounting ring in place from the rear.

These rings are simple to use when compared to normal metal electrical boxes since you do not need to find studs, this also allows for much more flexible placement.