FeaturesSupports most standard U.S. and Canadian boxes and plaster rings 4 sq-in, 4-11/16 sq-in, 5 sq-in and multi-gang electrical boxesCompatible with rapid ring self-adjusting pre-fab ring and adjustable plaster ringsMay be field modified for stud openings down to 6 in between studs (see reverse side)Ruler marks aid in positioning and alignment of electrical box and plaster ringPatent pending