The Sony MB-531 Dual Rack Mount Adapter is a rack adapter used to hold two Sony LMD-940W professional broadcast monitors side-by-side within a normal EIA 19" rack.
The MB-531 has an adjustable position for the viewing angle of the monitors, and if you only need to install a single monitor there's also an optionally-available blank panel to block out the space which would otherwise distract in the broadcast environment.