Bosch Mounting Box for Loudspeaker - 1

On top of the mounting ring, provisions are present to"click-on" the optional Back Box. The combination of Mounting Ring and Back Box prevents sound traveling via the ceiling cavity to adjacent areas, and fully protects the loudspeaker from dust, falling objects.The Back Box has knock-out holes for two grommets(11 mm/0.80 in) and for two cable glands (20.5 mm/0.80 in)