Loud and compact Whistle for your Keychain

**Please also check out my latest whistle designs:**

<a href="https://www.thingiverse.com/thing:5897001"><img src="https://media.printables.com/media/prints/417238/images/3464192_9b3f61e5-6690-4106-8901-1dc5d7f79685/thumbs/inside/1920x1440/jpg/image-4.webp" width="48%" height="48%"></a> <a href="https://www.thingiverse.com/thing:5950942"><img src="https://media.printables.com/media/prints/442546/images/3656273_e828690a-cf5a-4c82-a444-67215c6bd29a/thumbs/inside/1920x1440/jpg/title.webp" width="48%" height="48%"></a>

**Very loud dual-tone whistle**
I needed a compact and loud whistle to fit my keychain and couldn't find any design which fits my requirements. What I found was either too bulky, too fragile, or too quiet.

So I made my own design, and this are the key advantages:
- extremely loud for it's size,
- very compact, only 5 mm thick, 14.3 mm wide and 48.9 mm long,
- double tone, sounds similar to a referee's whistle,
- easy to blow,
- sturdy and hard to destroy,
- lean design,
- easy to print,
- fast printing (< 20 min), little filament required (approx. 2.5 grams).

**How to print:**
Use a line width of 0.4 mm and a layer height of 0.2 mm, 4 top layers and 4 bottom layers.

The whistle requires correct positioning of the Z-seam - it shouldn't be placed in the narrow air passages inside the whistle. The Z-seam should be positioned as shown in the image above (the white dots represent the Z-seam). Use the “Z Seam Alignment: User specified” option…