Model 7

C3 1/2 Advertisements for the C3 1/2, circa. late 1970s
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Company	Federal Signal Corporation
Produced	1938-1987
Type	Electromechanical
Sound output	113 or 108
Preceded by	Model 5 (1976)
Succeeded by	STH-10
Documentation	Manual

The C3 1/2, or commonly known as Model 7 was a 5, 7.5, and sometimes 10 horsepower, mechanical, omnidirectional siren produced by Federal Signal Corporation part of the Fedelcode lineup. The rotor in the C3 1/2 is 18" and shares it with the 500 Series and SD-10. Prior to the end of production, Federal decided to rename the Model 7 to the Model 5, as the Model 5 was already discontinued. There is no explanation known as of why Federal Signal decided to do this.

Model 7 was available in 3 different chopper configurations: 8 port single tone, 12 port single tone, and 9/12 port dual tone. The siren was housed in a very simple enclosure that resembles an air vent found on building roofs. The housing came in either painted steel or stainless steel.