Federal Signal created the "S" "small" 44 1/4" series light bar in the 1974. They created this light bar to offer smaller vehicles the ability to have the best light and sound product available on the market. The created a new frame with 4 breathing holes under the speaker. They also made a short speaker tray from metal and it was able to mount a TS24 under a shortened stainless steel speaker cover. The endcap of a small bar will be stamped with an S.