This little screwdriver with bit is a double side, in one end you can insert bit of 6 mm into other side you can insert bit of 4 mm. After print you need 3pieces of magnet 5mm diameter 2,5 thikness. This magnets should be inserted whit pressure by the 6mm exagonal hole into the 5mm diameter hole, they have a douple function : snap the bit ( 4 and 6 mm) and create a lock point for 4mm bit. If you don't use the magnets, the 4 mm bit will not remain in site, but go to the other hole for 6mm bit.
if you don't have the magnets, you can print the other stl, it don't have the hole for magnets. Enjoy

Anycubic

i3 Mega S/Pro

Doesn't Matter

15% is enough

Print temperature 240°C
Bed temperature 80°C