The MX 11R Comm is designed as a slide in replacement for the Narco Com 11, Com 11B, Com 111, Com 111B, and Com 120.
The unit will replace the Com 10 and Com 110 when the Nav 10 and Nav 110 are not used in the system. The MX 11R is the same unit as the earlier MX 11 except it does not come with the tray. You must order the tray seperately per the FAA.