How do I customize weight and measures?

When I create products I have a choice between imperial and metric. However, since I am in the USA, I only need the Imperial weights and measures.
I wasn't able to find a place to edit the available weight and measures. Is there a place in the administration where I can do that or is there a way to do it permanently (meaning that it doesn't get overwritten with the next update) in the code?

Thank you for your help.

Hi,

In Config > Main > Advanced settings, you can choose the desired symbols.
And this setting will be saved, even if you update. Configurations are saved in database.

Thank you very much. I don't know how I missed it but I did. Thanks.