This little hanging drill bit holder looks good and holds the bits securely. The inside is designed to be printed in TPU. I used a quite flexible TPU filament and it is very snug but the bits can be removed and inserted pretty easily especially a putting them in and out and wiggling them around a few times. Us a very low percentage of infill. If your TPU is not as flexible you may in to scale it a tiny bit. The outer PLA part slides on easily and stays on, but I gave the inside a bit of superglue so that the TPU part can never come out.