The FB-C6 enclosure is a flexible, pre or post-construction square acoustic foam box. Designed for 6.5-inch in-ceiling speakers (see full compatibility list below), the FB-C6 provides a better enclosed environment for the speaker, thereby improving the sound quality while also reducing sound transfer into other rooms. Using additional framing, the FB-C6 can be mounted in-between joists or trusses during construction or for post-construction installation, simply fold the FB-C6, push through the speaker’s mounting hole, and it will expand inside the ceiling. Once the FB-C6 is in place, install the speaker which, along with gravity and insulation, will easily keep the FB-C6 in position.