The shaker is an easy way to keep in rhythm. And to give a nice feeling for some songs. If you have ideas about an instrument that you would like to have and is possible to print. Contact with us, and we will design it. Plabs 3DI recommend for the lid an 80% infill or 100% so you ensure that the thread doesn't break. For the body no need for so much infill. 50% will be great. Anyway, you can try with less infill, as the sound will change and you could like it more. your choice... The 2 parts join up perfectly. I made them 2mm different so with printing precisions still made good mechanism. and I was amazed how perfect does it work. To improve the model, you can make a TPE or Soft PLA circle so the enclosure of both parts becomes airtight. Y filled mine with rice. But you can also try with lentils, peas, cents, or whatever you can imagine. Then...experiment with the sound and enjoy the music!!! If you have any instrument ideas, come to us and we will try to design them. Cheers from Plabs 3D