I believe this to be a RCA very high frequency speaker. The horn is spun aluminum and looks very similar to how the horn IB the Twin Power was made. This is just smaller, optimized for higher frequency use. I tested on my oscillator. I had the the voltage set to 2 volts and started at 2 KHz and swept up. Sounded loud and clean. I was able to hear it up to 14 KHz. After that it faded. Since I am older I think my ears faded first. The DCR was 6.7 ohms. I did try to unscrew the bell but it resisted. Didn’t want to force it so it will well packed and shipped in one piece. There is a wire screen at the throat and it is intact. Maybe some dust, could not get a clean picture of it. There is just one unit.
eBay