I recently acquired one of these for KWD. The design actually dates from the late 1930s. The 250K was virtually identical from the outside. By the time my 250L was built in 1947, the Art Deco period was really past, although this unit doesn't look anachronistic. The styling is beautiful. The transmitter, turntables, and console look like they were designed to go together--which of course, they were.
If you compare this transmitter to the BTA-1L at the top of the page, it looks like the BTA-1L is just two of these stuck together with a piece in the middle. In fact, one of the cabinets of the larger transmitter is a BTA-250L. It serves as an exciter and the power amplifier in the other cabinet boosts the output from 250 watts up to a kilowatt.