I received the following two images from flotrb to try to help ID Holton trombones.

Bruce --- WOW ! What a treat to see those Holton references to the Model 169 ! I owned one for several years right after they became available and enjoyed it immensely. I recently came across some quintet recordings in which I used it and after hearing those recordings I'm sorry that I ever let it go ! I had an opportunity to buy a custom Conn 70H with a Reynolds "F & E" setup that turned my head and so the Holton had to go --- to Ted Griffith, former bass trombonist of the Baltimore Symphony who was in transition to The Montreal Symphony. The setup was a little bit of a "Rube Goldberg" contraption, although it was quite effective in use. I'm pretty sure that there was a tuning slide on that "E"valve, but what a shame it wouldn't pull out far enough to be a "D" Valve. Good memories -- thanks !

Does anyone know anything about the 153? I can’t find much of anything on it on the internet.

Check out this site:

[url]<LINK_TEXT text="https://saxophone.org/museum/publicatio ... acturer/54">https://saxophone.org/museum/publications/museumType/1/manufacturer/54</LINK_TEXT>

Look for the Holton 1960 catalog