The JBL MTC-26TR is a trim ring kit allowing for the mounting of the Control 26C and Control 26CT ceiling contractor speakers into existing speaker cutouts that exceed the dimensions of those speakers and their normal cutout size. Trim rings allow installation of Control Contractor ceiling speakers into existing ceiling speaker cutouts that are larger than the speaker's normal cutout size. The maximum cutout size accommodated depends on the installation configuration.MTC-26TR for Models Control 26C and Control 26CT into cutouts up to 250mm (10 in) diameter.