This is my copy of a fantastic little whistle from my friend LeeBob.
https://www.printables.com/model/1576969-penne-20-public-domain-safety-whistle-cc0
https://makerworld.com/en/models/2322874-penne-2-0-public-domain-safety-whistle-cc0#profileId-2536984

This model is public domain, free and easy. Prints with no support and is loud enough to wake the President.

The text on the bottom is customizable to say what you like using the Thingiverse customizer or OpenSCAD. Here's what you can say:

1. Your name
2. Your dog's name
3. Your phone number
4. Something nice
5. Something cheeky
6. Your dog's phone number

Also customizable is the scale. The model at 100% size is approximately 37mm long. So far, I've tested it up to 140% and it works well.

The possibilities are endless. Print 759 of them and give them to your friends. Make earrings with them. Make a zipper pull. Put it on your keychain. Tape 204 of them to the handlebar of your bicycle and whistle while you ride.

Don't let me decide what you do with these. Let me know your ideas. Make someone smile.