This is an IKEA Skadis pegboard mount for the Klein K11095 curved wire strippers, using the T-Nut Mounting System: https://www.printables.com/model/228663-skadis-t-nuts-mounting-system-for-ikea-skadis-pegb
This model uses M2.5 bolts and nuts.
I recommend printing upside down with supports, though may be possible in other orientations.
The holder in the photos was printed in PLA with a .4mm nozzle, 0.2mm layer height.
The author marked this model as their own original creation.