You can't wear anything on the outside that is not an approved uniform item by UPS. That has to either be issued, or from the catalog. Brown, black or gray are for undergarments. Even then it says they can be brown or white.we're told not to sport any of our competitors colors. personally, i love the ups colors. During our training, we were told we can wear brown, black, or even grey. I just wanna know if i could wear a brown ballcap with a gold detroit logo on it or even an all black mets ballcap with a mets logo that can hardly even be seen.