YaeCCCST-5000 Step Up Step Down Transformer 110V to 220V Step Up Voltage Converter Transformer

Q: will 120v input give 240 v split phase output?

I don't believe it is true split phase 240. I tested mine and the 240V outputs appear to be floating. Ground however is passed through from the input cord to the output sockets.

Q: will it work for a 6-20p plug? where one of the prongs is horizontal instead of vertical?

The "universal" 220V socket looks like it *should* accept a NEMA 6-20P plug, which is pretty common. But I had to return a competing unit because the 220V "universal" sockets were apparently defective—the metal conductors appeared to be misaligned with the holes in the plastic front panel, and I could not get the plug into the socket.