Utilize Atlas Sound E410 Series recessed enclosures to mount hardware-free, torsion spring grilles. These enclosures are designed for use with 4" (102 mm) loudspeakers and are available with conduit knockouts (E410) to accommodate varying building code and installation requirements. This high-volume, 1/2 cubic foot (.014m3) version of Model E410 enhances the low frequency response of an installed loudspeaker. Model E410 - 11 has a depth of 11" (279 mm) and includes high-density fiberglass fill to absorb internal sound reflection.