Original type Coolidge tube (B.T.H. A2329 - A626)
Original type Coolidge tube (B.T.H. A2329 - A626), by British Thomson-Houston Company Limited, England, 1913-1939.
Original type Coolidge tube (B.T.H. A2329 - A626), by British Thomson-Houston Company Limited, England, 1913-1939.