Arm Board for a Microseiki BL91

Can anyone here advise me where to purchase an arm board for a Microseiki BL91 TT? Information seems to be rather scant on this subject.
They are expensive but may have what you want.
You might also try

They machine armbases for both the 1200- series (for tables like the BL-91) or armbases for the 1500/5000/8000 series.

You have to know what arm you want to use.