Loudest emergency whistle cap

I use the whistle as a recall for my dog. Which means I rarely use it, but keep it with me outside all the time - often with dirty hands etc. I designed this cap so the mouthpiece (as well as the holes that lead to it) remain clean. 

Print oriented with the cap vertical. 

If you have problems with the cap being too loose, or too tight, use horizontal expansion (cura) or XY size compensation (prusa slicer).