Dea Delta HA - Need help with extensions for probe

I have a DEA Delta HA gantry cmm and I am looking for some help with changing out the extensions. I have never had probe equipment like this. Just wondering the proper way to swap these out without
causing any damage. Can someone elaborate on the procedure? I also do not understand the probe options when building one of these. It has the extension length with two options.....without "MW" and with "MW"

Not sure what that means. I have added some pics.

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