I am not a dedicated player of low whistles but I nearly became one when I played one of these. They are eminently playable and are for sale on Ebay.
This will take you to the site: Hammy’s Low Whistle
This is one of my aluminium low whistles. The head is made from an aluminium core with a delrin plug and sleeve, held together by a brass pin. It is tunable. In designing this whistle I wanted to avoid two faults which I often saw in other low whistles. The first was the very uneven air pressure required to blow the bottom as opposed to the upper notes. On this whistle, one can blow strongly to get a powerful low D, and yet the upper end of the second octave and the lower end of the third don’t require a hard blow. Secondly, the response is flexible, by which I mean that one can move very easily from note to note making the playing of dance music at full speed absolutely feasible.The tuning capability comes from the head moving on the body tube. Dimensions you might like to know are: Overall length (slide closed) 606mm, body diameter approx.25mm, largest finger holes 12mm, smallest 8mm. I am very happy to answer any questions, and will mail a sound file on request. > Price includes shipping worldwide… > > (more on the auction site)> .
They aren’t mine and I have no financial connection to the sale. They come directly from Hammy.