Everything needed for most installations of these loudspeakers is provided with your Control Contractor ceiling speaker. However, a particular procedure that is sometimes used for installation into sheetrock (typically gypsum board) can be facilitated by the use of JBL’s optional pre-installation brackets before the sheetrock is installed. The pre-installation bracket provides a bracket to which wiring can be strapped in-place behind the sheetrock. It can function as a cutout template when many cutouts are to be made in a production-line style installation. And it can reserve a location in the ceiling prior to the sheetrock getting installed. The optional NC NEW-CONSTRUCTION BRACKET is made of flat sheet metal, with wings to attach to the building structure. Holes are drilled for nails or screws at 16" (406mm) and 24" (610mm) on-center. Additional holes can be drilled by the installer at other spacings up to a maximum of 24-3/4" (630mm) apart. Sheetrock installs after the bracket gets installed, and the bracket provides a template for blind cutout of the hole in the sheetrock. For this process, the sheetrock is typically cut with a router-type cutting tool, using the bracket ring as a cutout guide.