Greenhoe New York Style (Back Type) yellow brass mouthpiece pipe. For bass trombone (GB5). This is the longer (#1) of the two mouthpiece pipe types. Type: GB5 (Bass Trombone) Mouthpiece Pipe #1 Material: Yellow Brass Length: 220.7mm Throat Diameter: 12.6mm This is a used item, so there is some wear and tear, but it has only been used a few times. Please be aware of this.