Hi Does anyone have adjustable needle holders for sale?

I have a MC21 but it doesn't have adjustable needles. I have
a spare set of needles with the 5 grooves but not the rest that is
needed to replace it.

Can anyone give me some advice to what needs to be replaced to
be able to run the adjustable needles?

The code on the needles are: 5CEZ1
Are these A,B or C needles?