The Federal Signal Models 55 and 56 are electric horns that produce sound by means of a diaphragm, which resonates a column of air. Because the output is greater than that of a vibrating horn resonating horns can be used wherever a louder, more powerful signal is required.

Both models feature corrosion–resistant cast aluminum housings with a brass projector. These projectors are designed to match the frequency of the vibrating diaphragm to produce a smooth musical tone. The housings are tapped for 1/2" conduit (swivel bracket included).

Models 55 and 56 are finished in gray enamel and equipped with a straight projector. These weatherproof horns are water– and dust–tight when installed with conduit.

Model 55 is also UL (Underwriters Laboratories) Listed and CSA (Canadian Standards Association) Certified for indoor/outdoor use. Both models are FM Approved. Models 55 and 56 have a duty cycle of five minutes on, five minutes off.

Models 55 and 56 are ideal for both indoor and outdoor use. They require minimum maintenance; their rugged designs seal out corrosive dust and vapors. Both models have sufficient output to penetrate through high ambient noise levels.