imperial units dont have coolus helmets

[caeser44]

only my imperial legianary units dont have coolus hemets

[CaesarAugustus]

By the early second century AD, the Coolus helmet fell into disuse, so that is probably why Imperial Legionaires don't use them (a little early, but then again, so are the Marians and Augustans if you meet the reform criteria, so it's historically logical).