Conn 10H Small Bore Innes
Date: 1920. Owner unknown
The 10H Small Bore Innes or "Trill Valve Model" was produced from at least 1912 until 1930. The "small bore" suggests the bore was probably around a #1½ (0.458").
What Conn said in 1924:
The "Trill Valve" model possesses a valve which, when operated, changes the pitch a half tone. This feature enables the performer to execute many intricate passages with ease and assurance.