Date: 1920's. Owned by Michael Keller
The 10L is the Bb, Low Pitch version, the 11L is the Bb, High Pitch version.
What Conn said in 1928:
The "American Legion Bugle" was designed and built to meet the demand for a sturdy, reliable instrument at a moderate price. In general shape and size this model is like our regular trumpets, without valves, and it has a trumpet bore. It is an extremely popular instrument among the Legion and is also used extensively among Boy Scouts and other organizations.