Smart Box Inc. is like no other electrical box on the market today! The unique feature in Smart Box is the interior sidewall mounting screws. The interior mounting makes the box a great old work box. It makes no difference whether the walls are of sheetrock, paneling or plaster. The box is installed to a beam just as what would be done in new work construction. This makes for a sturdy installation at 1/3 the cost of the traditional old work box.