I have been given what I think is a flageolet. It has a little "spout" at the top to blow down, then six main holes on the front and a thumb hole. It's lowest note is a D. But there is also another tiny hole which takes it down to the c sharp below - I can see this could be very useful. Then it has six keys as well... I haven't worked out the fingering yet, but it seems to overblow quite nicely into a second - and even a third - octave.
I have tried looking up the flageolet site on the web but not found anything which matches up with my instrument. If anyone is a flageolet expert I would love to hear from you. I don't like possessing an instrument I can't play!