Classic pass-through letterbox for the In-Home bus with stainless steel front, V4A brushed. The flush-mounted housing GU CL BD3A 01 B-0 is required for flush-mounting. Components: . Door loudspeaker CBTLE 050-. with integrated loudspeaker and microphone, voice volume adjustable . 1 call button with backlit nameplate, replaceable on the front, acoustic feedback can be activated when a call button is pressed . 1 letter slot flap