That's a Federal Signal Twinsonic CTS. Steady red in front and flashing amber behind the red lamp. Both PAR-46s. Two rotating pairs of PAR-36s on each side. Rotators are in sync with each other by means of a chain driven motor.

Motor resides on the other side than the PAR-46s. It drives a gear cage turning the chains clockwise and counterclockwise.

BTW - CTS mean California TwinSonic. This style of lightbar is found in California due to a law over there calling for steady red in front and flashing amber in back.

Thanks FGS! Additional information of this vehicle is found at 1972 Dodge D-300.

Buffalo had the Twin-Sonic on the Battalion Chief vehicles during the 1970s. The only differences were that the steady and and flashing amber were absent and the siren was actually mounted on the hood rather than in the lightbar. This was a holdover from the earlier small rolling stock of squads and chief cars that had the single Model 17 Beacon Ray.

I posted a picture in one of the later episode at An English Visitor (#3.04) with the modern lightbar on the Battalion Chief vehicle shown here: