What is this device? (Constant level device?) Found this in my lab on a random shelf (water quality lab). It is old enough that nobody knows where it came from. I think it's a constant level device. It has in- and out-flow connections, as well as electrical plugs for some kind of monitoring equipment. The only writing is on the glass, which says "FSTREEM [ASTREEM?] MADE IN ENGLAND". The inside float looks like it is meant to float up and down, while the thin metal wire keeps track of its level via a small electric recorder. What is this thing called, and where can I find more info?

Thanks!
Thanks Joseph. Knowing that it is a Fi-Streem product, I called/emailed them and got an answer from their friendly support tech. From his email response: [This] is a "Switch Level Device, front" that is used in conjunction with an older series Fi-Streem (Fisions) Still, which is no longer manufactured. The part number for this item is, 06756."