Siren Whistles (One Dozen)

I asked my brother "hey do you remember those whistles we used to get that went whoop whoop whooo" and he said "the ones I used to cut down to the (metal blades back then) and put it in my mouth thinking no one would know where the noise came from?" "Yeah those" and he said "Carnival Source". He never said what he was looking for but there I was looking at all this stuff I haven't thought of or seen in years. Anyway the siren whistles were a big hit with all the kids young and old and just the right amount of noise not to be ear splitting.