Vintage USA Made 1/8 inch 3.175mm Shaft Bakelite Knob - Free Shipping
Shaft size is 1/8 inch(3.175mm), US standard.
Sizes in photos are in metric but you can convert to inch(1 inch=2.54cm).
Made in USA
The last photo shows the knob with a 1/8 inch shaft rheostadt(not for sale).
Free shipping via airmail takes 7-14 days to most parts of the world from Korea.
Some remote regions may take somewhat longer.