This is a third hand holder inspired on https://www.thingiverse.com/thing:2860825.
The joints are held by friction so its possible to adjust the position with a little bit of force. Its recommended to use metal washers between the screws and the arm pieces so the screws don't get loose.
A 25mm M3 screw and nut are needed on the jaw pivot point and a 20mm M3 screw is used to attach the Jaw to the Jaw coupler.
10mm x 5mm magnets can be press fitted into the base (three is good enough).
Beware the Crank, the CylindricalNutL and one side of the DualScrew are left handed threads.
See the attached 3mf file for suggested printing settings
The author hasn't provided the model origin yet.