I am actually very bummed that I have not gotten a chance to work on this machine and/or see it in person.
However, here are the pictures posted with author’s persmission.
It is a 4-push button knitting machine with the screw-on handle and a clip-on vintage row counter.
The buttons are activated using the special ratchet tool.
With the exception of the color, this machine looks and will probably act very similar to its other 4-pushbutton sister, Brother Profile 551, which I described in my blog in detail.
Because of its similarity with KH551, Brother KH531 might be compatible with the Brother KR551 ribber.