SWC 55171-S 4" OCT EXT RNG DRN 2-1/

2-1/8 in deep 4 in octagon plenum extension rings with four side conduit knockouts are used to provide added wire capacity to existing octagon (8B) boxes and provide access for additional conduit runs. Garvin' electrical box extension rings prevent the labor-intensive removal of older outlet boxes connectors and devices when extra wire capacity is needed. Adapter slots on the bottoms of the extension rings allow an easy slide on attachment to existing electrical junction boxes.