This tube fits 4 2" diameter bath bombs. This part is to store/gift them bath bombs which were made using the other items in the set.

The tube usees the fuzzy skin to press fit together and stay in place. The 3mf has it enabled to what I have found the ideal settings.

This tube can also be used to store for whatever else will fit. The acutal diameter is greater than 2" to accommodate the variation in spheres which are produced.