Red, 2-1/8" deep, 4-11/16" extension rings with (6) 1/2" and (6) 1/2"-3/4" knockouts are added to junction boxes to increase wiring capacity and provide access for additional conduit runs. They are painted red to easily distinguish them as fire alarm circuits. Garvin Industries’ extension rings prevent having to remove the old conduit boxes and wiring when additional wiring is needed. Their mounting slots allow a quick installation in existing boxes.