The Antoine Courtois AC260BO Performance Series F-Attachment Trombone is a great choice for the advancing student looking for a trombone with the step-up features of a slightly larger bore and F-Attachment. The Courtois AC260BO features a .525" medium bore combined with an open-wrap F-Attachment with miniball linkage. The adjustable thumb trigger allows the player to use the F-attachment with comfort, while the nickel hand slide allows quick action. The Courtois AC260BO Performance F-Attachment trombone includes a case and mouthpiece and is available in lacquer finish.