no answer in 3 days? i think a better title instead of "Inquiry" should have been "wanted: police hailer". generic titles tend to get ignored.
since i'm here, is this what you are after?
I've never heard of it before, but i'm sure with some decals, parts and a little ingenuity, you could easily scratchbuild one. make the bracket out of strip styrene and the posts out of tube styrene. the clear part could be cut from a CD jewel case or clear packaging (don't throw anything out without considering it's modelling potential).