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 MR PLASTER-RING BRACKET (or “Mud Ring”) contains a circular offset, forming an edge guide for sheetrock plastering. The bracket has wings that attach to the building structure. Sheetrock is typically either precut or cut with a rotary cutting tool using the outside of the plaster ring circle as a guide. The sheetrock hole is then plastered (or “mudded”) up to the ring to create a seamless cutout.