A circular stainless steel grille is an integrated with fireproofing acoustic damping enclosure protect against speaker and termination. Its buit-in 70 / 100V line matching transformer with multi tapping power output. The unit is screw visible use spring clamping into a hole in suspended ceiling or wall boards. The loudspeaker used in application airport terminals, bus / railway stations, sport / convection halls, hotels, hospitals, restaurants, office, department stores.