Hi, The Jinbei HD 600 II & V and the Rovelight 600 B are currently quite popular. Apart from their portability, it's their functionality with focal plane shutters used above their usual max sync speed that has caught people's attention. My unit under test is an HD 600 V.
I was keen to find out exactly what was happening in terms of flash duration when the units are operating both in normal mode and in "H" mode. (Note; scales may differ.)
Full power under both control modes, upper traces are 'Normal', lower are "H":