Krome Homebrew Stainless Racking Cane With Tip (1, A)

I cannot use this in my siphon without a rubber grommet. Which was the point of buying it. Do you have one for sell?

Just want to make sure this cane is .375 and not larger before purchasing. It needs to pass through a compression fitting.

Some reviewer said the cap was also stainless steel. That doesn't seem likely or correct. Can anyone confirm what material the cap is?

what size tube is needed