The MTC-TCD is (TCD stands for thick ceiling dogear) is an optional accessory dogear (rotating tab) for use with JBL control 24 Micro, 24 MicroPlus, 24, 26/19 in-ceiling loudspeaker models in thick ceilings. MTC-TCD dogears are designed to be used in ceilings up to 60 mm (2.4 in) thick. MTC-TCD dogears extend the usability to include ceilings up to 43 mm (1.7 in) thick.