My favorite is a jade shepherds whistle handcarved by a Maori craftsman from New Zealand. They aren't cheap and they require some practice to get the sounds you want. I tend to hand it from the rear view mirror and play "whistle to the oldies" when my dog's not in the car. If I can follow along with Bohemian Rhapsody, I can make about any sound I want. You can also get them in metal or plastic for a whole lot lessI've started reading up on how to train dogs to respond to whistle sounds and want to try this with (on?) Wally.
So of course, I want to get a good whistle so that it makes a quality sound and is easy to use/adjust the pitch.
To that end, I was wondering if there are any whistle trainers/handlers and what whistles they like to use or have had good experiences.