The M&S RT11 Remote Transformer has been discontinued. A similar replacement is the RT35 Remote Transformer. Note that the replacement is hard wired, not the plug in style of the RT11.
The RT11 transformer is a 24 Volt AC with center tap, UL Listed, 40 VA plug-in wall transformer that is used as a power supply for the MC11M Master and the DRW Door Release Mechanism. Included is a 50 ft., 4-conductor cable.