BELL No. 57 | |||||||
Trembler bell for preliminary signal and special cases in Post Office buildings. The Mark 1 is wooden cased whilst the Mark 2 has a plastic casing. The Mark 2 was introduced circa 1957. Bell No. 57B is pictured below. Diagram - N657. Drawing - 90903 (Mark 2). Specification - S2.
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Last revised: July 11, 2022FM |