This is an unusual example of an early Bach Stradivarius model 8 trombone with the variation of model 8ii stamped on the bell. It is suggested that the model 8ii later became known as just the model 8. Note the bell brass gauge marking of 51 versus the standard 45 commonly used.
Also, looking for anyone that can explain the marking of “33” on the main support.
[source: Barry Goldberg]