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The thing is I bought the chauvet 375z irc and could not find it in the list of chauvet's lights in freestyler so I wanted to try to control the 375z irc with freestyler using the file for the 355z irc
I am not shure where you are looking but you need to add the fixture.
Setup-> Add/remove fixtures.
Find the Chauvet folder and search for the fixture.
Note somehow they are not listed 100% alphabetic. You may have to search the whole Chauvet folder to find it.