Tried this in Blender 4.2, 4.2.1, and 4.3 Beta - same issue as others have stated about the scale, it doesn't seem to scale based on the Units selected.
I use millimetres and then have to scale the Bolts by 1000 before they are usable and can be seen.
It is a great extension, but the 0.4.2 introduced a bug where the bolts are too small. If you add a bolt in your scene but you can't see it, just scale the object.
Tried this in Blender 4.2, 4.2.1, and 4.3 Beta - same issue as others have stated about the scale, it doesn't seem to scale based on the Units selected.
I use millimetres and then have to scale the Bolts by 1000 before they are usable and can be seen.