What is an F attachment or “trigger” on a trombone?
The F attachment or “trigger” is a rotary valve added to the trombone, mostly found on larger bore models. This valve is operated with the thumb, and works like the fourth valve on a euphonium or tuba. When added to the slide, it drops the pitch to a lower harmonic series. For example, play a first position middle F, add the trigger, and you can now play a C below the F in first position. This increases the low range of the trombone and also offers additional alternate positions. There are many types of valve available for the F attachment, many with the goal of more closely matching the feel and sound of the “straight” trombone (one without a trigger). The rotary valve is the most common, with the Thayer, Hagmann, Greenhoe, Christian Lindberg, and Bach K valve available as well. The “open wrap” style of tubing is also a popular option, although some players still prefer the traditional (closed) wrap. The open wrap has fewer bends in the tubing, “opening” up the feel and sound of the t
