3-1/2" deep, 4" square junction boxes with old work clips and plaster ears and (8) 1/2” & (4) 1/2”-3/4” side knockouts and (3) 1/2”, (2) 1/2”-3/4” bottom knockouts are added to existing walls when deep devices (speakers, strobes, etc.) are required to update a structure. Garvin Industries’ labor saving design eliminates the need to awkwardly install boxes and extension rings to accommodate deep devices.