JBL JBL-MTC-424MR Mud Ring Bracket for Control 424C/T

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.