Shift Knob, shift shaft diameter

Is it a Vintage Speed shifter?  I replaced mine with a 356 knob.  It was nicer to grab because it was not open on the bottom like the original knob. It wasn't cheap.  I think it is  10mm.  You can remove the knob and try a 10mm nut on it.

Generally speaking the Vintage Speed shifters come in either a m10x 1.5 thread or m12x1.5 thread… depending on the model.

As suggested above, a good way to confirm is to try a 10mm or 12 mm x .5 thread pitch nut on the shifter shaft, or just take your knob to a Home Depot//hardware store and test fit a bolt of either of the two sizes mentioned above…  our local Lowe’s /Home Depot has a bolt/nut test sizing board with all the metric sizes in their bolt aisle which make sizing identification quick and easy.

Also, just for your reference,

- the classic original style 356A shifter knob is 10mm - m10x1.5.  https://www.stoddard.com/nla24...ivo-nla24305ivo.html

- and the early VW ones with no shift patter can be had at places like Cip1 in either size..  https://www2.cip1.com/search-r...=products&page=2

once you have confirmed the thread size you can shop for your preferred accessory… lots of options out there.
Happy hunting…

@swan4356

Post a picture of your shifter. Our early cars did not come standard with Vintage Speed Shifter as they do now.

Greg

As requested, pictures are attached.  VM build 2021.

Thanks for everyone's advice,

Looks like vintage speed shifter

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As Phil says, that's a Vintage Speed shifter.

Mine came with a 10mm thread and looks like this without a boot:

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