Looking for vinyl pants

I am making a set of speaker cables with 12/3 braided copper. The overall diameter of the cable is 1/2". I am trying to find some 'H" vinyl pants but not having much luck. I'm in Canada and relying heavily on Amazon but all the pants they send me are too small in diameter. I though maybe I need 12mm. Any suggestions folks?

TIA
 
Speaker cable pants

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