I've been printing a lot of masks but with no way of hanging them. This won't work for all, but may be useful to some. I printed mine in PETG. No need for supports.
Update**: Added a more stout version with longer pins. You can scale either to fit the depth required.
| MaskMountShort.stl | 70.7KB | |
| Mask_Mount_v2.0.stl | 71.8KB |
