i've seen more clipper guards with mm than with those single digit numbers, which is good because those numbers told me nothing, if i recall correctly they do not match the hair lenght they'd cut to but instead are just numbered from smallest to biggest in the set
but instead are just numbered from smallest to biggest in the set
And, critically, are different between manufacturers and probably between sets for different razors from the same manufacturer. If it was at least semi-standardized, like shoe size, we'd get used to it
Interesting. Is this often what is used in other countries perhaps? I'm an American and I've always been asked in terms of inches. I'd guess centimeter would be used most other places.
In NZ, they ask what number, and it's a single digit, like number 3 or number 5. 3 is cut shorter than 5, but I don't know what the unit of measurement is