Thanks to the interests.
This photo shows us switch area of Arago rollers.
It was just written by Japanese though I think most of people can use it if they don't read Japanese.
It's very simple.
I made notes to the Flickr photo so confirm it if you want to know the meaning.
I think there is no problem only to use if not to be able to read Japanese.
In fact, I've not read any of something like construction papers.
But this roller needs electronical power and ofcourse it compatible with Japanese common power source, 100V.
So I think you need a converter plug for 100V though not to need Japanese
I measured the rollers and the adjustment length was about 6cm.
This num is not specialy short length I think because my other folding rollers by Minoura has similar ajust length.
Wheel base of the white colored pist racer is 960mm.