Pellet pouch, inspired by Wilkins leather pellet pouches. It holds something like 150 4.5mm airgun pellets. Because of inner rim and flat back, you can lay it onto the ground and take pellets one by one when shooting without the risk of pellets rolling out. Or you can hang the pouch on your neck/side.
Usage of supports depends on your printer - if the object is positioned correctly, you shouldn't need them.
To avoid opening, glue small (diameter up to 5mm) neodymium magnet to the lid and a piece of ferromagnetic metal to the bottom to hold the lid closed.