Hey, Tyresa here! I made these hair clips with pretty much the leftover foam from the headphones and random things around the house ^^ It took less than an hour ^^
At least.. after 2 failed attempts. The first time, I made it too small and it wouldn't fit the pony tail. The second time it was too big and fell off. Third time's the charm ^^ so PLEASE use my measurements
=] It will fit exactly, with a little room to maneuver around the wig clips.
Miku Headset Tutorial: [link]
Reference image used in tutorial: [link]