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.
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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.