The Monorail Wall 4 Inch Round Canopy by Edge Lighting Monorail Wall 4 inch round canopy is mounted on the wall behind the Monorail Wall run. It is mounted to a standard junction box with plaster ring, or octagon box, where the low voltage leads from the remote transformer (sold separately) are connected. Use with Monorail Wall standoff's. Finish available in satin nickel, polished nickel, or antique bronze. ETL listed.