Extend existing electrical boxes instead of pulling out and replacing them by using these rings. They're commonly used where tile, drywall, or another layer of material has been added to the surface. Attach the rings to the existing box to add more depth when you need more space for wiring devices. They can also be used to close a gap so switchplates and covers set flush with the surface.
Also known as masonry box extension rings, these rings are typically used on concrete, brick, block, or other thick walls. The extenders add depth to an existing electrical box so it can sit flush with material surfaces.
Often called plaster rings, mud rings are used in drywall or plaster surfaces. They have a flange that helps cover gaps or irregular cuts in a wall.