It is used to carry your earphone in bag well organized. It is contained in this closed case, which make sure that it won't tangle with everything in your bag or get damaged. the middle piece, I separated them into two pieces in order to print without any support, because personally I don't like the printing quality with support. It has one hole on each side, to adapt different earphone length to have the end out. I am thinking to upgrade it into a rotating core, may update it later when i have time :) PS: the file is updated. I upload wire_mng-3 with two openings now. the previous one was the wrong file with only one opening hole.