This solid external unit for surface mounting is equipped with a built-in colour camera, loudspeaker and microphone. It is finished in up to 4 mm thick aluminium and the surface-mounting height is merely 16 mm. The external unit is equipped with a nameplate which can be personalised and will only be illuminated in the dark. The colour camera is equipped with infrared LEDs for a better visibility at night. The metal-plated push-button contacts are maintenance-free and durable. This external unit has 1 bell.