Boy the these manufactures must think we are stupid. I recently had to have a 46mm socket according to my caliper. This actually coverts to 1-13/16" SAE. When pricing one locally they were wanting nearly 15 usd more than metric label one vs the SAE labeled one. It is the same size socket so I ordered the Sunex SAE deep well impact socket through Amazon for 21 usd with free shipping instead of the 47 usd locally plus shipping. The locals wanted 60 usd for the metric labeled one. All I got do is to the 46mm on it. Anyway it the biggest socket I now have in my toolbox.
Lesson here is to check the conversion info and to shop around before buying tools.