I’ve got a Holton TR-183 single valve bass George Roberts played one of these for a while. I have a great sound the slide is about a 7/10, it has a good bit of lacquer wear and dings on bell and tuning slides. Valve compression is great and both tuning slides move freely. I’m looking for a dual valve bass trombone for orchestra playing let me know if you’re interested and I can send some pictures.