Model VP410-S Unidirectional vandal-proof baffle/enclosure is designed for use with standard 8" (203mm) loudspeakers. Model will also mount an APF Series flange mounting horn with the aid of a adapter plate Model FAMT-6. The VP410-S works only with the APF-15 8? horn, not compatible with APF-15T transformer version due to height constraints. Housing is constructed of spun .090 tempered aluminum plate for maximum strength and rigidity. To prevent any possibility of tampering from the rear of the baffle, the rear edges are slightly regressed to allow the baffle to be drawn tightly against the ceiling. Grille trim ring is cast from special, self-aging aluminum alloy with a tensile strength of 44,000 P.S.I. (twice that of conventional aluminum castings). Loudspeaker grille is reinforced with a stainless-steel, woven, wire mesh screen spun over a 21-gauge perforated CRS subplate. Final assembly is completed using flush-mount, heat-treated alloy screws. These tamperproof screws are countersunk to enhance security (special wrench provided). Model mounts to standard E.O. boxes (not included) via keyhole slots on the rear of the housing. It may also be flush mounted with anchors (by others) to the ceiling or wall for more secure and rigid installation. Baffle and housing are finished in satin aluminum with a clear, lacquer coating.