JBL MTC-442MR Ceiling Speaker Mud Ring Bracket for Control 442 (Pack of 6)The JBL MTC 442MR is an optional mud ring bracket used with Control 400 Series ceiling speaker installations in sheetrock or gypsum board applications. It supports pre install planning by reserving the speaker location before the sheetrock is installed and provides a point to secure wiring behind the surface. The circular offset forms an edge guide for plastering, helping create a clean finished cutout. Its winged bracket design attaches to the