A smaller frame (-15mm) of the genius Print Plus 3d printed headphones (https://www.print.plus/) , fitting for smaller heads of children or in my case my girlfriends head :D

Print settings are the same as with the original one.

Print instructions

0.40mm nozzle for high detail & good fit
print frame separately by itself for best mechanical properties
ensure lines on same layer melt well together (no gaps between lines) as well that layers themself melt well together to ensure good mechanical properties
0% infill
1.2mm (minimum) wall thickness
1mm top &bottom layer (minimum)
print without support
print without brim/skirt/raft (mini-brim modeled into 3D model)

i used PETG , but PLA should work too.