This is a clone of the invisiLav, a holder / mount for the smartLav that goes under your shirt or collar. It hides the mic and reduces noise from clothing. Use a medical double sided tape to attach it to your chest or undershirt.
Use flexible (TPU) material and less than 5% supports (this will make it softer). Then simply push the mic in until it's just below the opening on the other side.
Print it standing (hole pointing up), you don't need any supports.
If you want to use PLA, you'll probably have to scale it up by a few percentages for the mic to fit.
The author hasn't provided the model origin yet.