The CM Series Flush Mount Ceiling Loudspeakers are designed for low ceiling applications in a public address system. The loudspeakers utilise torsion springs for easy installation and to eliminate visible mounting screws. The CM Series consist of 6 models: CM 361 ( 75 mm transducer ); CM 461/CM 461E ( 100 mm transducer ); CM 561E ( 130 mm transducer ); CM 611/ CM 611E ( 160 mm transducer ). All models come with a multiple impedance line matching transformer, suitable for 70V or 100V distributed loudspeaker system. Suffix ‘E’ which follows the model name, denotes that the model comes with a metal back enclosure.