This is a King tenor-bass trombone, model 4B, serial number 2104. This model has been discontinued. It's a rare tenor-bass trombone from King. The bell is gold brass, and the slide is nickel. King is often associated with jazz, but this instrument has a rich and powerful sound, making it suitable for concert bands and orchestras. I am selling it because I can no longer play due to health reasons. There are three small dents on the bell and minor rust on the rim. The slide and other moving parts function smoothly without any problems. If you wish, I will also include the Denis Wick 6BL mouthpiece and the Hercules stand (with rust repair) shown in the photos. I also have some remaining oil and grease, which I will include. If you don't need them, please let me know and I will dispose of them. Please feel free to ask any questions you may have.