Bowser / Cal-Scale 190-550 – Nathan P3R4 Air Horn
The Cal-Scale 190-550 is an HO scale Nathan P3R4 air horn, cast in unpainted brass. It is a single-piece locomotive detail part intended for adding a realistic Nathan P3R4 horn to an HO scale diesel locomotive. Current Walthers and Bowser listings both identify the part as a Nathan P3R4.
