Warburton backbore 7. Compatible with Kanstul and others. For more detailed information on size, shape, playing feel, and for used or new mouthpieces, please search on Net Brass. There is some plating wear and scratches on the shank. Please check the images. There are no major scratches or dents that would interfere with playing. Please refrain from comments asking for a price reduction. Instant purchase OK. Type: Trumpet Type: Trumpet (in C / B flat)