half-size?? - are you sure??
SEE: http://www.kaybass.com/
Kay produced a
1/4 bass, (M-3), along with at least three different sized cellos. The H-10, S-10,
M-3, and S-3 are all the same size and have the same string length. In early years, the quarter bass was called the H-10. About 1954 the H-10 was renamed the M-3.
Double check your serial number (above link) for date . . .
1/4 or 1/2 - ?? Are you looking for a small instrument as compared to a full (3/4) sized bass?