What is an F Attachment and what is it used for?
After a student starts learning the trombone and associating with other trombonists and band members, it isn’t long before he/she sees a trombone with all kinds of extra tubing on the back end and says, “COOL!” If the instrument’s owner is present the conversation will go something like this:
“What is all that?”
"F attachment” (or “a trigger”)
“What does it do?”
“Plays 6th position.” The player shows how to play a low C
“Cool! What does it cost?”
With a flick of your thumb, you divert your air through that additional tubing and lower the fundament pitch of your instrument from B-flat to F. An F attachment can make some of the more difficult passages easier to play and it will extend the range of the instrument down past low E, assuming the player has the air and the chops to play down there. I use it, there’s hardly a serious player out there who doesn’t use it, but as a teacher I would advise AGAINST upgrading to a trombone with the F attachment at least until the player’s starting High School or otherwise fairly accomplished. With too many young students it gets used simply to avoid 6th and 7th position and they never get comfortable with the longer positions of their slide.