I prefer a ruler, that way it’s completely unambiguous and clear to everyone. Well, unless you use a ruler marked only in inches when your audience is not from North America or the UKCould you post a picture with something to get an idea of the size. A paint pot is the 'standard' measure on here as they are easy to judge....
I find it funny when people use a coin, I'm like 'OK how bit is a 10c or a 1€ coin. lol.
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