The loudspeaker unit is a 6 W, dual-cone loudspeaker
with an integrated circular metal grille. A 100 V
matching transformer is mounted on the back. The
appearance and neutral white RAL color have been
selected to be unobtrusive in virtually all interiors.
The loudspeaker has built-in protection to ensure that,
in the event of a fire, damage to the loudspeaker does
not result in failure of the circuit to which it is
connected. In this way, system integrity is maintained,
ensuring loudspeakers in other areas can still be used
to inform people of the situation. The loudspeaker has
ceramic terminal blocks, thermal fuse and heat-
resistant, high-temperature wiring. It can also be fitted
with an optional fire-dome to increase protection of
the cable termination.

All Bosch loudspeakers are designed to withstand operating at their rated power for 100 hours in accordance with IEC 268-5 Power Handling Capacity (PHC) standards. Bosch has also developed the Simulated Acoustical Feedback Exposure (SAFE) test to demonstrate that they can withstand two time their rated power for short durations. This ensures extra reliability under extreme conditions, leading to higher customer satisfaction, longer operating life, and much less chance of failure or performance deterioration.