The Bosch LBC 3951/11 Ceiling Loudspeaker Box of 10 provides powerful sound in a compact easy-to-install loudspeaker. The speaker's wide opening angle provides a maximum listening range. The LBC 3951/11 has a perforated metal grille with a plastic surround, finished in an attractive off-white RAL color The loudspeaker features a very wide opening angle, which means fewer units are required to cover a given area. The wide frequency range means better speech and music reproduction. The unit is supplied with a 100 V matching transformer with taps on the primary winding for full-power, half-power, quarter-power and eighth-power radiation The loudspeaker (with special treated paper cone), is IPx4 water protected from the front and can be applied in humidity environments for example bathrooms, saunas, atriums and swimming pool areas All plastic parts are manufactured from self-extinguishing high-impact ABS material (according to UL 94V0) 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 times 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