Inexpensive wall speaker, suitable for the reproduction of speech and background music in e.g. storage rooms, stairwells, etc. The ZL 135 G offers a high level of efficiency and a wide dispersion angle due to its 135 mm broadband chassis with additional tweeter cone. A volume control and/or program selector switch, also with 24 V mandatory call relay, can be integrated as an option. Installation is carried out using two screws. , A plastic rear panel is available as an accessory.