Now here’s a rare gem! A Bach 42B Corporation with a valve made by Bernie Marston. Those are the valves used on the legendary Mount Vernon Bach trombones, they are just a little bigger than the valves Bach used afterwards. Only a few trombones of the Corporation era with that valve exist. As you can see the brass used on the valve section is just a little more red than the rest of the horn.
The instrument is in great condition with only a little lacquer wear.