AtlasIED 8" Blind-Mount enclosure systems ( U.S. Patent # 4,673,149 ) provide an easy and cost-effective alternative for secure speaker installation in retrofit ceiling applications. All necessary hardware is provided including a unique support system with mounting ears that telescope out from inside the enclosure and adjust vertically to accommodate ceilings with a thickness of 1/2" (13mm) to 1 3/8" (35mm). Units feature CRS construction and include torsion-spring receptacles for quick mounting of torsion-spring grilles. (J-Nuts are included on the return of the enclosure to accommodate surface-mounting grilles.) To allow cable access, enclosure backplates are manufactured with three 1/2" (13mm) conduit knockouts. Enclosures are also equipped with sound damping material to minimize metallic resonance.