with microphone, loudspeaker and electronics for easy connection to the TCS:BUS, very good voice quality, volume and microphone sensitivity adjustable, prepared for the connection of further bell button extensions, integrated bell button wiring, metal bell buttons with gold-plated and maintenance-free button contacts, long-lasting lighting using LEDs, shatter-proof name plate cover made of 5 mm thick plastic glass, name plate size 72 x 74 mm, any bell button can be used as a light switch button, light symbol is included, control tone for the visitor when the bell button is pressed, very easy assembly and installation, temperature range: -20 degrees C to +50 degrees C, color: aluminum painted white, dimensions: 166 x 135 x 20 mm