Dual tube whistle

I wanted a decent small loud whistle I could print and give out to people where I work. I downloaded several whistles and printed them but could not find one that worked reliably. So I decided to make my own. I started with a small metal whistle that I have carried for years, and tweaked the design until I got something that is loud and, at least on my Rostock Max V2, prints reliably.

One of my goals was a reasonably fast print. At first I had to print at 0.1 mm to get a good whistle, but I