1) Whistle Small. Whistle Small was my first whistle. It is easy to print, requires no supports, and makes a somewhat pleasing sound in a moderate pitch. I printed this whistle at .1mm vertical resolution with 20% infill and no supports. 2) Whistle Tri-Tone. Whistle Tri-Tone was my second whistle and I liked it because my youngest grandson loves to blow it when we play with the Balloon Powered Single Cylinder Air Engine Toy Train (https://www.youmagine.com/designs/balloon-powered-single-cylinder-air-engine-toy-train). I printed this whistle at .1mm vertical resolution with 20% infill both without and with supports. Without supports, there will be minimal clean up inside the whistle mouthpiece. I used a small modeling knife and a flat jewelers file and in less than a minute, the clean up was complete. With supports, it was simple to break away the supporting material from inside the mouthpiece using small needle nose pliers. With supports you must be careful not to let the slicer put support material in the whistle tubes as it is very difficult to remove (I wonder how I figured this out?). Using Cura 2.3.1, I have the slicer only print support material that is in contact with the build plate, which works great. 3) Whistle Tri-Tone Staggered. Whistle Tri-Tone Staggered makes the tri-tone sound as does Whistle Tri-Tone, it just requires a little less plastic to do so. I printed this whistle at .1mm vertical resolution with 20% infill both without and with supports. Without supports, there will be minimal clean up inside the whistle mouthpiece. I used a small modeling knife and a flat jewelers file and in less than a minute, the clean up was complete. With supports, it was simple to break away the supporting material from inside the mouthpiece using small needle nose pliers. With supports you must be careful not to let the slicer put support material in the whistle tubes as it is very difficulty to remove (see the previous whistle). Using Cura 2.3.1, I have the slicer only print support material that is in contact with the build plate, which works great. 4) Whistle Slide. Whistle Slide was my last whistle. This whistle produces a variety of tones as the whistle slide is moved into and out of the whistle. Since my grandkids, some quite young, would be playing this whistle, I wanted to print it solid and in one piece to increase the effort required to disassemble it (and perhaps chew on a small piece). In order to print this whistle in one piece, supports are required primarily to break contact between the whistle slide and whistle body. I printed this whistle at .1mm vertical resolution with 100% infill and with supports. Using Cura 2.3.1, I had the slicer print supports "everywhere", but increased the "support overhang area" from 60 to 70 degrees. This kept the slicer from placing support in the upper end of the whistle tube which would lock the slide in place, which is not good for a sliding whistle. I tested these settings using Cura 2.3.1 layers view mode before printing in order to avoid printing a sliding whistle that wouldn't slide. Once printed, I carefully removed the support material from the whistle mouthpiece and in and around the slide using small needle nose pliers. Those are the whistles, I hope you like them!