Arlington Industries FER102-10 Expandable Outlet Box with Mounting Wings, Old Construction, 10-Pack, Non-Metallic, 2-Gang. Box comes ready to install as a two-piece two-gang box. Includes mounting wings to securely mount box onto drywall with existing construction. Use in conjunction with FER102C center sections when a larger box is needed, to build up to a ten-gang box. Just snap together units to create your sections, save on time and money with your projects. With the center sections you can forget the time consuming way of making multiple gang steel boxes out of several single-gang boxes. Adjustments are easy - use screw driver in between sections and twist to separate, save on time and money. To use - start with the FER102 and determine how many gangs are needed, use center sections (FER102C) to add one gang to the box for up to 10-gangs, snap ends of the original two-gang box to each side of center sections, mount unit to drywall with built-in mounting wing screws. UL Listed - Industry standard for safety and performance.