This is a printable cap to make a slovakian overtone flute known as a fujara.  I based my design off information found here http://flutopedia.com/fujara_craft.htmThe length of PVC needed will depend on the key you want to tune your fujara to. The cap should work for key of G and possibly A and F. I haven't tried to tune and cut the finger holes yet so I am not positive but the information I used was for a key of G.If you want to glue the cap on once you have a properly tuned fujara you will need some ABS to PVC transition cement and is sold at home improvements stores, I have some made by Oatey.So, print the cap and tube barb, superglue the tube barb in cap and push on 4'-6' of vinyl tubing. Follow online instructions at the site I linked to earlier and tune your fujara. Once you have the length tuned, cut the finger holes.Don't have to generate supports to print, it has one in the model.  Just use a sharp knife and run it along the labium lip a couple times as shown in the picture, it will pop right out. Tube barb needs to be rotated 180 degrees before printing.It is a tight fit so you shouldn't have to glue it onto the pvc...in fact, I suggest beveling the outside edge of the pvc a little before pressing the cap on, and use a twisting motion when you push it on.Want one of these but don't have a 3D printer? Try this https://www.3dhubs.com/dallas/hubs/dfw-maker-depot/3dprint